Since the 10th season the closing credits start playing over the final scene; the screen shrinks so the title bar showing the credits can become visible.
Normally the footage for the title credits changed each season, being composed of footage from the new season's episodes. However, the 10th, 11th and 12th seasons had the same opening credits as the 9th, possibly because starting with the 9th season it became standard for episodes to be delayed one season (episodes shot for season 9 were aired as season 10 and so forth).