Are the Clippers—the historical lesser of L.A.’s two basketball teams, without a single championship to its name—worth $2 billion?

Former Microsoft MSFT CEO Steve Ballmer thinks so. And while the media has widely criticized his offer, a team is worth whatever someone is willing to pay.

But before the team’s recent ownership storm, predicated by soon-to-be-former owner Donald Sterling’s caught-on-tape racist rant, the Clippers were only worth $575 million, according to an annual ranking of sports team valuations from Forbes. In fact, American sports teams in general, since the 2012, have sold, on average, for 55% more than the most recent Forbes franchise valuation of the team. (And even without taking into account the Clippers sale, which does skew things, the Forbes valuations are still low by 34% on average). This isn’t so much a knock on our competition as an acknowledgment that is is almost impossible to predetermine what these highly sought-after assets would receive on the open market. And this is a note that if the last two years are any indication, the value of these franchises are only going to continue to rise.

Here are the last 10 major American sports teams to get sold, and their selling price vs. the most recent Forbes valuation at the time when the team sold.