Year	Number of
1990	393.77
1991	401.19
1992	410.31
1993	419.34
1994	428.53
1995	437.31
1996	449.27
1997	459.87
1998	470.11
1999	479.47
2000	488.85
2001	487.48
2002	486.75
2003	488.72
2004	491.1
2005	493.79
2006	497.76
2007	502.6
2008	508.84
2009	515.98
2010	523.87
2011	523.9
2012	523.92
2013	523.3
2014	523.95
2015	526.12
2016	528.07