Table:
text: Stadio Ennio Tardini
League attendances
League attendances
Season Average High Low Season_tickets_
2001–02 Serie A 17956 27498 14704 12156
2002–03 Serie A 16306 25603 12980 11544
2003–04 Serie A 15904 23663 11463 10439
2004–05 Serie A 14044 23010 10711 9923
2005–06 Serie A 14372 23116 11575 10639
2006–07 Serie A 14644 20488 11946 11120
2007–08 Serie A 15427 25149 11890 11386
2008–09 Serie B 10031 12265 9261 
2009–10 Serie A 17061 21323 11870 13691
2010–11 Serie A 14524 19615 11975 10578
2011–12 Serie A 13646 19481 10800 9620
2012–13 Serie A 12740 19073 9627 10546

Question: How many seasons has the stadio ennio tardini had an average of at least 15,000 visitors?