Across the country, many teenagers are bombarded with messages from parents and teachers that they need to attend college in order to succeed financially. But the reality is, a significant portion of high school students simply aren't cut out for higher education. Many of these, from Bill Gates to Mark Zuckerberg to Coco Chanel, managed to do quite well despite never completing a university degree.

To be sure, many athletes have perfected their skills while playing at the collegiate level before turning pro and becoming millionaires. Even so, quite a few achieved athletic success and (parlayed it into substantial earnings) without ever setting foot on a college campus.

Until recently, this unorthodox career path was most commonly associated with the NBA. Household names like LeBron James, Kobe Bryant, Dwight Howard, and Kevin Garnett were drafted straight out of high school and into the pros until the league instituted a minimum age. So for the purposes of this article, we're going to omit NBA stars as they have their own article, which can be accessed here.

But there were plenty of athletes in the past that made it big in their respective sports without ever entertaining the notion of college. From Muhammad Ali and Pele to Wayne Gretzky and Lance Armstrong, these sportsmen forwent college to begin plying their trade in the professional ranks - and were rewarded handsomely for it. Of course, there were numerous baseball players who followed this path - from the early days of Babe Ruth, Willie Mays and Hank Aaron to more modern-day greats like Pete Rose, Ken Griffey, Jr., and Cal Ripken, Jr.

And even in 2014, there are quite a few sports stars who never enrolled in college courses but still became multi-millionaires. Here are ten of the most prominent who are still earning major coin today (excluding those who play in the NBA).

10. Usain Bolt, Track and Field

It's no stretch to say that Bolt is the "fastest" man to crack the Forbes 100 Richest Athletes list. As of last summer, Bolt earns an eye-popping $24.2 million annually, with all but $200,000 of that coming from endorsements. The Jamaican speedster spent his teen years winning regional and junior track and field championships, and then captured gold in the 200 meters at the IAAF World Junior T&F Championships at age 15 in his backyard of Kingston. The remainder of his teen years were spent recovering from a series of injuries before reemerging on the world stage at the Beijing Olympics in 2008, winning three individual gold records while shattering a trio of world records - all at age 21.

9. Sidney Crosby, Hockey

No matter how old Crosby gets, he'll still always be known as "Sid the Kid" to many who saw him skate as a youngster. Crosby learned to skate at age three and has been lapping his peers ever since. At the ripe old age of 14, Crosby appeared in two games for the Truro Bearcats, a Junior A Hockey League team. By the time most kids enter college, Crosby had donned a Pittsburgh Penguins jersey and made his NHL debut in October of 2005 at age 18. He proceeded to become the youngest player in league history to notch a 100-point season. Then he garnered numerous other honors before captaining his club to the Stanley Cup in 2009 - all before turning 22. In 2013, Crosby earns about $4.5 million in endorsements in addition to his $12 million annual salary with the Pens.

8. Roger Federer, Tennis

Who says you need a college degree to make good bank? As of last year, Federer was the second-most highly-paid professional athlete in the world (trailing only Tiger Woods) with an annual salary of $71.5 million, although his endorsement earnings outnumber his prize money 10 to 1. But like many college students, Federer had to battle some homesickness on his way to success as a child. He was accepted into Switzerland's national tennis development program at age 14 and had to leave his Basel home to train near Lake Geneva, where he was the youngest participant (and didn't speak French very well). Nevertheless, Federer persevered and won his first ATP tournament in 2001 at age 19, then won his first of 17 Grand Slam titles 2 1/2 years later at Wimbledon.

7. Josh Hamilton, Baseball

Unlike the three previous entries on this list, Josh Hamilton's teenage years were relatively unorthodox as compared to his peers. He played high school baseball in Raleigh, North Carolina, where as a senior he ran a 6.7 second 60-yard dash and had a fastball that was clocked at 97 mph. As a result, the Tampa Bay Devil Rays drafted Hamilton out of high school as an outfielder with the top overall selection in the 1999 major league draft, giving him a signing bonus of just under $4 million. But like many other people his age, Hamilton began experimenting with drugs and alcohol shortly thereafter, which eventually resulted in a full-season suspension by MLB in 2006. Hamilton then made his major league debut in 2007 with the Cincinnati Reds, and after putting up huge numbers with the Texas Rangers, he now plays for the Los Angeles Angels of Anaheim under a five-year, $125 million contract.

6. Tony Hawk, Skateboarding

The San Diego native stepped on an old, scratched-up skateboard for the first time at age 9, and the rest is history. Tony Hawk began winning amateur contests in California at age 12, then turned pro two years later. By the time he was old enough to have a driver's license, Hawk was widely considered the world's top skateboarder. He began earning endorsement money which put him ahead of what many of his high school teachers made in a year. But then pro skateboarding's popularity disappeared in 1991 when Hawk was graduating. No worries; instead of enrolling in college, Hawk started a skateboard company. Eventually, he expanded into skating apparel, and was perfectly positioned when the sport reemerged into prominence several years later. Today, Hawk is worth an estimated $120 million.

5. Rory McIlroy, Golf

The Northern Ireland native was close to matriculating at a higher education institution in America, actually signing a letter of intent to play collegiate golf at East Tennessee State University at age 15. But after his success in Europe the following year, McIlroy opted to keep playing amateur golf on the continent. He turned pro in September of 2007 at age 18, when he otherwise would have been enrolled in his first college classes. Instead, he continued to perfect his game, earning his first pro win in Dubai seventeen months later. McIlroy has since won ten other tournaments, including the 2011 U.S. Open and the 2012 PGA Championship. Last year, Forbes reported that he earned almost $30 million in pro winnings and endorsement money. He'll reportedly marry longtime girlfriend, tennis star Caroline Wozniacki, in New York later this year.

4. Lionel Messi, Soccer

Ranked as the 10th-most well-paid athlete in the world by Forbes with net annual earnings of $41.3 million (almost evenly split between salary and endorsements), Messi's ascent is even more remarkable when you consider he was diagnosed with a growth hormone deficiency at age 11. Thankfully, the Argentinian youth was signed by football club Barcelona, who agreed to pay for his medical bills. Messi continued to impress on the pitch in the lower age groups, so much so that he earned his first start for the top-tier squad at age 16 in a friendly in November of 2003. He made his first La Liga start less than a year later, and has been a star forward for Barcelona pretty much ever since.

3. Alex Rodriguez, Baseball

More recently, A-Rod has been known as the poster boy in MLB's version of the war on drugs, and has been banned for the entire 2014 season (even though he did earn $3 million for not playing this year as per his contract terms). But people forget that Rodriguez turned down a scholarship offer from the University of Miami after being taken first overall by the Seattle Mariners in the 1993 MLB draft. He made his major league debut in July of 1994, just a few weeks shy of his 18th birthday. Upon free agency in 2000, Rodriguez signed an astonishing ten-year, $252 million deal with the Texas Rangers (which was 33% higher than the second-richest contract at the time). He was later traded to the New York Yankees in 2004, crossed paths with performing-enhancing substances... and you know the rest.

2. Maria Sharapova, Tennis

She's just a hair behind the aforementioned McIlroy on the Forbes Richest Athlete list, with estimated annual earnings of $29 million. Undoubtedly, Sharapova appreciates her wealth more than many of her rich peers, having arrived in the U.S. from the Soviet Union at age 7 with her father and just $700 to their names. Two years later, she enrolled in the prestigious Nick Bolleteri Tennis Academy in Florida. Sharapova won an international junior tennis tournament in 2000 at age 13 against players three years her senior. She won her first adult pro tournament at age 16, and became the first Russian-born woman to be women's tennis's #1 player at age 18. She has won each Grand Slam tournament once, and has gone on to earn fortunes in the apparel and candy world as well.

1. Shaun White, Skateboarding and Snowboarding

It became clear early on that the phenom who eventually began known as "The Flying Tomato" would be destined for fame and fortune without having to attend any classes at a university. White garnered his first snowboarding sponsorship at age 7, and was also mentored in skateboarding by the aforementioned Hawk at age 9. When his peers were struggling through college, the 19-year old White won his first Olympic gold medal in 2006 at the halfpipe event in Turin (and defended his title in Vancouver four years later). He also has five X-Games skateboarding medals and 18 X-Games snowboarding medals. These days, White earns about $7 million each year for endorsing big-name products like Oakley, Red Bull, Target, and GoPro.