Year	Number of
1990	166.07
1991	174.31
1992	184.52
1993	194.27
1994	207.02
1995	218.77
1996	223.86
1997	237.21
1998	253.81
1999	274.49
2000	298.34
2001	320.16
2002	344.7
2003	374.97
2004	405.63
2005	434.52
2006	447.84
2007	463.4
2008	482.56
2009	501.54
2010	522.73
2011	543.69
2012	561.64
2013	577.97
2014	597.01
2015	618.17
2016	641.64