Year	Number of
1990	20152.7
1991	20388.47
1992	20656.24
1993	21005.75
1994	21319.73
1995	21743.87
1996	21963.12
1997	21763.15
1998	22297.95
1999	22632.86
2000	22870.93
2001	22990.52
2002	23130.5
2003	23294.75
2004	23364.78
2005	23537.14
2006	23861.03
2007	24207.86
2008	24535.86
2009	24792.71
2010	25037.6
2011	25122.1
2012	25316.81
2013	25238.04
2014	24670.33
2015	24668.95
2016	24687.28