Year	Number of
1990	128.34
1991	127.26
1992	128.31
1993	127.1
1994	129.4
1995	133.37
1996	135.55
1997	133.37
1998	133.27
1999	136.8
2000	142.51
2001	147.37
2002	152.01
2003	156.54
2004	162.88
2005	168.13
2006	174.07
2007	179.7
2008	187.57
2009	198.79
2010	208.35
2011	217.44
2012	225.61
2013	233.27
2014	239.61
2015	246.89
2016	255.72