Year	Number of
1990	160.11
1991	155.48
1992	150.04
1993	142.89
1994	134.12
1995	131.09
1996	124.83
1997	127.15
1998	120.71
1999	120.11
2000	120.31
2001	125.7
2002	134.66
2003	141.06
2004	144.68
2005	151.58
2006	157.61
2007	162.71
2008	167.09
2009	169.96
2010	172.94
2011	177.19
2012	180.63
2013	182.89
2014	185.46
2015	189.79
2016	197.05
