Year	Number of
1990	329.06
1991	332.61
1992	333.36
1993	331.07
1994	330.37
1995	333.11
1996	341.6
1997	353.67
1998	370.13
1999	388
2000	406.43
2001	424.95
2002	445.39
2003	470.51
2004	496.46
2005	522.82
2006	538.63
2007	552.93
2008	567.45
2009	582.52
2010	598.87
2011	609.19
2012	621.34
2013	634.31
2014	647.28
2015	659.83
2016	672.06