Year	Number of
1990	17989.43
1991	18187.23
1992	18335.73
1993	18528.74
1994	18766.39
1995	18937.06
1996	19020.1
1997	18832.55
1998	18541.48
1999	18383.78
2000	18316.86
2001	18245.33
2002	18274.02
2003	18210.24
2004	18179.56
2005	18313.48
2006	18367.25
2007	18391.66
2008	18567.4
2009	18652.71
2010	18638.61
2011	18571.39
2012	18516.67
2013	18491.26
2014	18336.13
2015	18325.25
2016	18429.71