Year	Number of
1990	16593.08
1991	16781.24
1992	16957.48
1993	17109.62
1994	17276.33
1995	17470.24
1996	17552.8
1997	17638.21
1998	17711.44
1999	17759.41
2000	17852.73
2001	17929.6
2002	17969.36
2003	17987.38
2004	18036.99
2005	18149.14
2006	18126.93
2007	18106.79
2008	18081.95
2009	18084.44
2010	18139.43
2011	18475.85
2012	18818.77
2013	19157.75
2014	19459.49
2015	19770.23
2016	20091