Year	Number of
1990	82.57
1991	85.78
1992	92.6
1993	98.55
1994	110.01
1995	118.35
1996	125.62
1997	132.39
1998	141.89
1999	146.19
2000	147.31
2001	145.59
2002	145.71
2003	149.2
2004	154.52
2005	156.71
2006	162.02
2007	166.84
2008	172.28
2009	175.71
2010	179.68
2011	182.93
2012	184.44
2013	185.07
2014	188.22
2015	192.3
2016	197.56