Year	Number of
1990	125.58
1991	127.18
1992	129.23
1993	131.12
1994	133.31
1995	135.56
1996	138.14
1997	137.13
1998	136.66
1999	135.31
2000	135.04
2001	132.1
2002	131.34
2003	132.53
2004	135.54
2005	138.23
2006	140.19
2007	141.59
2008	144.5
2009	148.47
2010	154.55
2011	160.37
2012	165.96
2013	171.02
2014	176.67
2015	182.12
2016	188.16