Year	Number of
1990	397.37
1991	399.37
1992	395.06
1993	386.8
1994	377.74
1995	375.76
1996	379.46
1997	376.32
1998	379.13
1999	369.97
2000	363.93
2001	361.52
2002	357.53
2003	356.34
2004	353.21
2005	350.42
2006	347.92
2007	345.25
2008	344.61
2009	339.94
2010	337.21
2011	331.61
2012	326.78
2013	325.34
2014	316.8
2015	316.63
2016	318.74