Sports as a business is doing just fine — well, mostly. Although the NHL may not  currently have a business, the NBA and NFL are seeing record revenues, and baseball is seeing television money flow in like never before.

Well, hold on right there, because not all teams are doing that well. In fact, the website 24/7 Wall St. identified the 13 top-tier sports franchises in North America that are losing fans at the fastest rate. According to their methodology, “Based on 10-year change in attendance of home game of teams in the four major sports leagues — NHL, MLB, NBA and NFL — 24/7 Wall St. identified the teams with the worst declines in attendance.”

The team suffering the worst decline? That would be the Seattle Mariners,  not only whose “average attendance declined a major league sports-leading 51.4%, but stadium capacity last season was an MLB-low 44.4%.”

In fact, if you’re a baseball fan, the news isn’t all that good. The top four teams on the list — Mariners, Indians, Astros and Diamondbacks — are all baseball clubs, with the Dallas Stars coming in at fifth. Other teams in the unlucky 13 include the Detroit Pistons, New York Mets and Miami Dolphins.