Year	Number of
1990	243.89
1991	242.62
1992	236.77
1993	228.64
1994	221.63
1995	217.4
1996	240.36
1997	265.68
1998	301.29
1999	330.46
2000	353.23
2001	360.29
2002	368.66
2003	369.95
2004	373.99
2005	380.91
2006	394.28
2007	407.7
2008	418.84
2009	429.77
2010	442.17
2011	455.35
2012	471.72
2013	495.56
2014	523.34
2015	554.8
2016	585.89