Year	Number of
1990	434.06
1991	402.51
1992	384.53
1993	370.78
1994	353.81
1995	339.31
1996	332.49
1997	325.54
1998	313.53
1999	334.25
2000	354.78
2001	383.9
2002	416.23
2003	451.39
2004	495.77
2005	532.65
2006	560.43
2007	578.54
2008	590.29
2009	606.09
2010	630.74
2011	661.69
2012	697.94
2013	745
2014	790.53
2015	830.42
2016	879.26