The movie and TV show catalog at Netflix has reportedly shrunk by more than 50% since 2012.

According to the streaming site Exstreamist, which cites former Netflix nflx employees and the website uNoGS (which stands for Unofficial Netflix Online Global Search) the number of titles carried by Netflix in the U.S. fell from a peak of some 11,000 in 2012 to 5,300 in September 2016.

Several forces have led to this decline, Extreamist reports. On one side, some content owners have turned to other distribution channels to get more lucrative deals. Seinfeld, for example, went to Hulu in an exclusive streaming deal reportedly worth $180 million. Meanwhile, shows like 24, King of the Hill, and the Doctor Who reboot have all disappeared from Netflix at various points.

On the other side, Netflix has turned its attention to creating more original content, a move that began in 2011 when chief content officer Ted Sarandos paid a reported $100 million to buy the U.S. rights to House of Cards.

As Michal Lev-Ram wrote in the Fortune story “How Netflix Became Hollywood’s Frenemy” in June:

Netflix is encroaching on the big screen too, outbidding incumbent studios for high-profile projects like Bright, a Will Smith cop thriller it snapped up for a reported $90 million this year. More alarmingly, it has been lobbying against traditional theater-only cinematic runs for new movie releases—leading John Fithian, CEO of the National Association of Theatre Owners trade organization, to call out Netflix at a recent conference as a “grave threat to the movie business.”

A third reason for the reported shrinkage could be Netflix’s steady overseas expansion. The streaming and online media site notes that Netflix has more than 13,500 titles in its global catalog, but only some 5,000 in the U.S.

Netflix declined to comment on the reported drop in the number of titles in the U.S. catalog. “Overall, we are adding lots of new content, spending $5 billion this year to add original and licensed content to the service,” a Netflix spokesperson said in a statement. “Traditional content licensing agreements mean it’s pretty common for shows and movies in any catalog to change over time.”

Whatever the reason, the reported catalog shrinkage appears to be just another step in Netflix’s evolution, which has had its rocky moments—a miss in subscriber growth numbers sent shares down some 15% in mid-July—but that has been largely attributed to price increases, not catalog cuts. Time will tell.

This story has been updated with the response from Netflix.