Year	Number of
1990	124.45
1991	129.36
1992	134.58
1993	140.86
1994	149.11
1995	153.36
1996	153.56
1997	154.87
1998	158.87
1999	161.56
2000	162.6
2001	165.43
2002	168.47
2003	167.43
2004	168.09
2005	168.59
2006	172.84
2007	176.33
2008	179.16
2009	183.56
2010	187.47
2011	191.06
2012	195.98
2013	200.23
2014	203.66
2015	207.95
2016	211.78