Year	Number of
1990	146.2
1991	146.03
1992	153.73
1993	152.5
1994	144.02
1995	150.34
1996	159.3
1997	159.7
1998	165.36
1999	162.23
2000	154.03
2001	157.88
2002	155.09
2003	159.82
2004	161.99
2005	169.66
2006	175.02
2007	170.39
2008	175.8
2009	174.4
2010	174.24
2011	170.57
2012	168.73
2013	159.79
2014	152.3
2015	155.22
2016	153.79