Attendance at new MLB ballparks

This year the Minnesota Twins expect more than three million fans to come Target Field in downtown Minneapolis to watch the team - up from 2.4 million last year in the Metrodome. That's typical of the increase new ballparks enjoy in their first year. But a sustained boost isn't the guarantee that it was 10 or 15 years ago.

Over the last decade, several teams -- including Milwaukee and Pittsburgh -- have seen attendance drop off 20 percent or more as soon as the second year after opening a new ballpark.