Players in this sport earn more than the others

* NBA leads sports with average pay of $4.6M
* American leagues more equal than European
* Petrodollars propping up new soccer clubs

LeBron James #23 of the Cleveland Cavaliers drives against Stephen Curry #30 of the Golden State Warriors during Game One of the 2015 NBA Finals at ORACLE Arena on June 4, 2015 in Oakland, California.
Getty Images
LeBron James #23 of the Cleveland Cavaliers drives against Stephen Curry #30 of the Golden State Warriors during Game One of the 2015 NBA Finals at ORACLE Arena on June 4, 2015 in Oakland, California.

The performances of Stephen Curry and LeBron James Sunday night in game five of the NBA Finals show how unequal the distribution of talent can be among professional basketball players. The stars scored 37 and 40 points, respectively, in the Warriors' defeat of James' Cavaliers to pull ahead in the series 3-2.

But when it comes to pay, the NBA is actually more equal than many sports leagues around the world, according to data from sports analytics site sportingintelligence.

Overall, NBA teams have the highest average pay of the 17 professional leagues studied in sportingintelligence's annual global sports survey report. The Brooklyn Nets top the list of basketball teams with average annual pay of $6.2 million for the 2014-15 season, according to the report. The Cavaliers and the Warriors—the teams battling it out in the finals now—are ranked 8th and 9th on the list, with average annual pay of $4.9 million.

Sportingintelligence uses a calculated metric they call "average first-team pay," which is meant to make up for the number of players on a first string team for the different sports. Soccer, for example, could have 25 players considered while for basketball, the pay for 13 or 15 players was considered.

Using a statistical measure called the Gini coefficient, CNBC looked at the level of equality between teams in each of the 17 leagues. The Gini coefficient, which is often used to describe levels of income inequality between nations, is a figure between 0 and 1. If a nation's Gini coefficient is 0, it means that all citizens have the same income, while if it's 1, it means the nation's income is entirely in the hands of a select few citizens. The 28 nations that make up the European Union have a Gini coefficient of 0.3, according to eurostat, far below the U.S.'s 0.41.

But the opposite is true when it comes to sports.

It turns out that European sports leagues tend to be less equal than American leagues in their distribution of average annual pay. The Scottish Premier League—with its Celtic team making six times any other team—has the highest Gini coefficient, at 0.53. Spain's La Liga is also above 0.5, with Barcelona and Real Madrid ranking high as outliers.

Stateside, it's the all-American NFL that has the most equal distribution of pay. The NFL's Gini coefficient is 0.04, ranking it 14th among the leagues. Sportingintelligence doesn't include endorsement deals or any other outside pay in its report.

Read More Why does Tom Brady make so little in endorsements?

Major League Soccer has a Gini coefficient of 0.31, the highest among American sports. That's interesting because like the NFL, MLS has a salary cap that should—theoretically—keep salaries within the same ballpark. But each MLS team has "designated" players whose salaries aren't counted towards the cap, which adds to differences within the league. "The salary structure of the MLS seems to offer a perfect recipe for inequality," two researchers at the Harvard Sports Analysis Collective recently wrote.

Overall, the most well-paid team is PSG, from the French Ligue 1. As the report points out, PSG's inclusion on the list this year shows the growing influence of "petrodollars of oil-rich Middle East nation Qatar." Players for PSG, which is owned by a Qatari sovereign wealth fund, average over $9 million in annual pay.

Bayern Munich, the powerhouse of German soccer, are far and away the top-paid team in the Bundesliga, with average annual pay of $7.7 million. Bayern has won six out of the last 10 league championships and the team features a number of players from Germany's national squad.

But a high average pay doesn't always mean absolute success. The two possible NBA champions—the Golden State Warriors and Cleveland Cavaliers—are the eighth and ninth basketball teams on the list. They have average annual pay of $4,946,195 and $4,890,102, respectively.