Year	Number of
1990	18757.15
1991	18774.61
1992	18892.01
1993	18977.82
1994	19022.95
1995	19040.65
1996	19005.17
1997	18877.68
1998	18671.68
1999	18294.25
2000	18059.42
2001	17880.08
2002	17647.02
2003	17459.04
2004	17289.21
2005	17202.29
2006	17155.39
2007	17140.8
2008	17198.84
2009	17325.69
2010	17441.79
2011	17630.46
2012	17849.03
2013	18130.79
2014	18350.74
2015	18574.6
2016	18738.39