Year	Number of
1990	88.71
1991	91.5
1992	94.63
1993	98.16
1994	101.89
1995	105.89
1996	109.1
1997	112.45
1998	115.9
1999	119.45
2000	123.19
2001	124.28
2002	125.63
2003	127.25
2004	129.61
2005	132.96
2006	137.63
2007	142.93
2008	149.21
2009	154.37
2010	157.9
2011	160.96
2012	162.1
2013	162.19
2014	163.05
2015	165.92
2016	168.85