Year	Number of
1990	147.48
1991	151.28
1992	156.48
1993	162.3
1994	167.66
1995	172
1996	171.37
1997	166.92
1998	168.46
1999	167.42
2000	165.2
2001	168.47
2002	172.81
2003	178.09
2004	180.27
2005	184.36
2006	188.06
2007	193.31
2008	199.16
2009	199.34
2010	201.66
2011	208.06
2012	212.86
2013	216.78
2014	224.2
2015	232.55
2016	240.63