Year	Number of
1990	859.59
1991	835.06
1992	813.41
1993	784.16
1994	744.85
1995	718.17
1996	683.96
1997	647.31
1998	635.75
1999	605.64
2000	578.95
2001	578.75
2002	562.94
2003	535.82
2004	516.26
2005	503.07
2006	498.36
2007	493.55
2008	495.61
2009	495.37
2010	499.17
2011	509.84
2012	517.82
2013	515.17
2014	506.58
2015	514.83
2016	518.91