Year	Number of
1990	132.03
1991	133.99
1992	134.99
1993	135.26
1994	136.06
1995	138.06
1996	138.46
1997	139.68
1998	141.64
1999	143.85
2000	146.13
2001	150.47
2002	154.99
2003	160.85
2004	166.34
2005	171.5
2006	175.88
2007	180.34
2008	184.77
2009	188.94
2010	192.53
2011	196.34
2012	199.37
2013	201.79
2014	204.71
2015	208.89
2016	211.4