Year	Number of
1990	226.9
1991	233.69
1992	241
1993	248.67
1994	256.77
1995	265.53
1996	272.27
1997	280.62
1998	284.38
1999	291.27
2000	300.84
2001	304.48
2002	313.14
2003	319.42
2004	324.63
2005	329.51
2006	332.81
2007	335.07
2008	340.99
2009	344.3
2010	354.61
2011	367.63
2012	373.4
2013	382.65
2014	393.49
2015	405.29
2016	421.21