Year	Number of
1990	259.8
1991	269.13
1992	279.64
1993	291.29
1994	302.92
1995	313.06
1996	324.62
1997	336.28
1998	348.52
1999	363.3
2000	379.98
2001	394.28
2002	408.39
2003	424.51
2004	442.89
2005	462.51
2006	475.6
2007	487.9
2008	500.12
2009	511.55
2010	523.47
2011	539.4
2012	556.36
2013	575.55
2014	595.17
2015	615.09
2016	636.16