The way i see it, 2001 and to a slightly smaller extent 2002 were the two outliers. As Rudolf suggested, it's not due people just wanting to spent more time in theaters for random reasons but LOTR, HP and Bulli. The most recent spike was in 2009, the year of Avatar. True, admissions in the last 7 years (except 2009) are down compared to the 7 years prior on average by about 15% but again, it could be just that the right movies weren't around, Bulli and HP lost their luster, no LOTR around.