Year	Number of
1990	312.44
1991	313.36
1992	313.93
1993	314.62
1994	314.78
1995	314.62
1996	322.82
1997	330.73
1998	338.1
1999	345.22
2000	352.29
2001	358.23
2002	363.88
2003	368.75
2004	373.43
2005	378.4
2006	381.3
2007	384.39
2008	388.53
2009	393.25
2010	398.79
2011	403.06
2012	408.61
2013	414.46
2014	421.11
2015	428.49
2016	437.19