Year	Number of
1990	114.75
1991	117.37
1992	122.12
1993	125.33
1994	133.46
1995	146.69
1996	147.59
1997	150.39
1998	150.55
1999	151.11
2000	154.88
2001	155.91
2002	157.28
2003	156.43
2004	157.61
2005	158.26
2006	160.92
2007	162.21
2008	163.54
2009	165.28
2010	170.05
2011	173.44
2012	175.82
2013	179.93
2014	184.69
2015	190.15
2016	197