Year	Number of
1990	134.48
1991	134.14
1992	136.09
1993	138.38
1994	142.9
1995	146.29
1996	147.71
1997	152.17
1998	151.45
1999	152.4
2000	151.36
2001	149.15
2002	149.14
2003	153.95
2004	156.39
2005	160.04
2006	164.14
2007	169.31
2008	174.56
2009	180.1
2010	184.52
2011	188.45
2012	196.87
2013	203.46
2014	210.84
2015	218.68
2016	227.72