Year	Number of
1990	372.97
1991	377.15
1992	391.76
1993	401.14
1994	408.79
1995	413.76
1996	423.29
1997	433.62
1998	421.67
1999	413.51
2000	410.69
2001	382.6
2002	377.34
2003	366.18
2004	363.38
2005	369.27
2006	365.3
2007	376.43
2008	377
2009	388.7
2010	403.54
2011	409.93
2012	416.32
2013	429.23
2014	460.91
2015	502.47
2016	528.53