Year	Number of
1990	209.65
1991	213.48
1992	215.81
1993	214.26
1994	215.79
1995	212.61
1996	213.89
1997	211.97
1998	210.02
1999	203.99
2000	201.14
2001	205.88
2002	205.5
2003	202.04
2004	202.97
2005	201.29
2006	193.12
2007	188.78
2008	190.31
2009	189.39
2010	191.99
2011	198.21
2012	205.26
2013	211.9
2014	218.33
2015	227.18
2016	234.87