Year	Number of
1990	102.7
1991	106.81
1992	110.84
1993	117.52
1994	124.22
1995	131.01
1996	137.18
1997	143.04
1998	148.73
1999	153.29
2000	154.05
2001	153.71
2002	154.19
2003	158.44
2004	161.8
2005	165.72
2006	172.59
2007	182.64
2008	194.93
2009	206.97
2010	215.31
2011	216.58
2012	217.66
2013	218.15
2014	219.39
2015	222.82
2016	225.55