© 2012 Daily Tennis News Wire -
The disparity between the ATP's haves and have nots is growing, according to  a study by USA Today, which tracked trends from 1990-2011.

The study indicates that the world's top three of Novak Djokovic, Rafael Nadal and Roger Federer have been more dominant in terms of prize money than any trio since the tour was formed, grabbing between 20% and 26% of total  prize money over the past five years. The only other top three to take in over 20% of the total  was Federer, Nadal and Andy Roddick in 2006. Prior to 2006, no threesome had every combined to grab 20% or more.

As USA Today pointed out, the disparity is not that stunning considering that since 2009, Djokovic, Nadal, and Federer have won 11 of 12 majors and 17 of 27 of the Masters 1000s.

Many tournaments are now heavily weighting prize money to the winner. At the current BNP Paribas Open at Indian Wells,  the difference between the finalist and winner is $500,000, with the winner's check at $1million.

When billionaire owner Larry Ellison decided to up the prize money at this year’s BNP Paribas Open, he stipulated that $700,000 of that would go to the final three rounds.

The winner's check jumped 64% from $611,000 to $1 million from the previous year. However, first-round losers did not see the same increase, getting an 8%. bump from $7,709 vs. $7,115

From 1990 to 2011, total ATP prize money went from $33.8 million to $80.1 million in 2011, a 137% increase.