Year	Number of
1990	146.82
1991	152.22
1992	155.21
1993	157.76
1994	162.17
1995	165.73
1996	170.43
1997	172.54
1998	176.05
1999	177.62
2000	177.73
2001	177.62
2002	179.01
2003	179.62
2004	180.36
2005	181.56
2006	182.68
2007	182.49
2008	182.18
2009	181.89
2010	185.96
2011	188.08
2012	189.19
2013	192.69
2014	195.86
2015	199.29
2016	203.79