Year	Number of
1990	183.17
1991	184.24
1992	186.76
1993	189.23
1994	192.14
1995	195.43
1996	199.33
1997	202.82
1998	204.35
1999	204.31
2000	208.7
2001	212.57
2002	210.36
2003	210.85
2004	207.77
2005	205.17
2006	205.17
2007	209.3
2008	213.97
2009	218.79
2010	221.39
2011	224.91
2012	227.82
2013	231.18
2014	234.34
2015	237.42
2016	240.96