Over the last few weeks I've been playing with some data visualization platforms as a way of presenting a historical look at how Major League Soccer salaries have changed over the years. Last week's release of a new set of salary data provides an opportunity to put those tools to use.

The MLS Players Union has published salary data for every player in the league at least once per season since 2007. In some years, there have been multiple publications. As I started to analyze the changes over time, I realized that to keep some level of consistency it would be best to use the final data set published each year.

With all of these charts, you can hover over the lines to get specific data points.

Let's start with some noteworthy salary trends. Here is a look at how the mean (average), median (middle), mode (most common) and lowest leaguewide salary have changed over the years:

That is all good news for players. And as you might imagine, along with those figures, the total amount of spending leaguewide has skyrocketed over the last eight years:

2007: $42,223,660.07
2008: $47,292,509.20
2009: $51,878,050.49
2010: $71,304,972.70
2011: $85,079,475.83
2012: $99,257,881.30
2013: $95,078,142.32
2014: $129,531,839.47
2015: $167,569,743.03

That is nearly a 400 percent increase in spending (396.86 percent, to be precise) over the last eight years. It becomes even more stark when you compare that increased to the increase in the number of players in the league:

Here are those numbers in graphic form:

Consider the rise in spending not just in the context of the lesser rise in the number of players, but also in the trend lines of the median and minimum salaries. And when it comes to this year in particular, the new collective bargaining agreement factors in. That deal secured a significant raise in the minimum salary, but also cut each team's roster size by two players.

At the other end of the pay scale, here's a look at how many players each season have earned at least $1 million in guaranteed salary:

It becomes clear that while a great many players have gained from the increase in leaguewide spending, some players have gained more than others. Though it's also worth pointing out that while the number of millionaires has risen considerably since 2007, the highest individual salary in the league has not:

I'm sure many of you know who topped the salary chart in those years. For those that don't, here's the list.

2007: $6,500,000.04 (David Beckham, Los Angeles Galaxy)
2008: $6,500,000.04 (David Beckham, Los Angeles Galaxy)
2009: $6,500,000.04 (David Beckham, Los Angeles Galaxy)
2010: $6,500,000.04 (David Beckham, Los Angeles Galaxy)
2011: $6,500,000.04 (David Beckham, Los Angeles Galaxy)
2012: $5,600,000.00 (Thierry Henry, New York Red Bulls)
2013: $5,038,566.50 (Clint Dempsey, Seattle Sounders)
2014: $6,695,188.75 (Clint Dempsey, Seattle Sounders)
2015: $7,167,500.00 (Kaká, Orlando City)

Put all that data together and you get to where we are now: an era of unprecedented spending in MLS, but still with some significant disparities in how that spending is distributed. This line chart is in some ways an overly simplistic representation of that distribution, but it still makes a point. You can slide your cursor along the line to get data points for various players across the league:

Finally, here is a graphical representation of every salary in the league grouped and color-coded by team. Inquirer graphic artist John Duchneskie put it together. As you'll see, it shows the differences not only in individual salaries, but in how much each of MLS' 20 clubs spends on salaries.