Year	Number of
1990	248.7
1991	261.7
1992	280.51
1993	302.57
1994	319.06
1995	336.79
1996	347.76
1997	358.58
1998	372.29
1999	385.69
2000	400.34
2001	403.55
2002	406.78
2003	411.39
2004	416.53
2005	429.25
2006	439.33
2007	450.39
2008	462.19
2009	475.45
2010	489.77
2011	505.37
2012	524.25
2013	543.29
2014	567.58
2015	594.68
2016	620.86