Year	Number of
1990	105.02
1991	102.58
1992	99.05
1993	95.54
1994	93.6
1995	94.02
1996	97.46
1997	102.87
1998	110.04
1999	116.39
2000	121.43
2001	122.7
2002	123.36
2003	122.96
2004	122.96
2005	123.69
2006	127.67
2007	132
2008	136.74
2009	141.69
2010	146.95
2011	152.42
2012	158.52
2013	165.51
2014	172.95
2015	180.77
2016	188.53