Year	Number of
1990	359.99
1991	360.14
1992	364.07
1993	373.02
1994	381.98
1995	395.76
1996	401.33
1997	411.71
1998	418.06
1999	428.77
2000	439.59
2001	448.76
2002	458.98
2003	466.83
2004	474.91
2005	482.61
2006	490.39
2007	487.77
2008	488.11
2009	485.65
2010	484.81
2011	483.45
2012	484.78
2013	490.29
2014	498.18
2015	508.5
2016	519.63