Year	Number of
1990	194.03
1991	203.54
1992	217.25
1993	233.15
1994	248.45
1995	264.08
1996	270.23
1997	275.31
1998	279.54
1999	285.03
2000	293.99
2001	300.17
2002	310.7
2003	323.11
2004	336.15
2005	350.62
2006	365.74
2007	379.67
2008	395.5
2009	413.06
2010	433.87
2011	450.98
2012	472.21
2013	494.96
2014	518.6
2015	542.74
2016	569.46