Year	Number of
1990	19831.61
1991	20131.68
1992	20534.77
1993	20954.91
1994	21250.22
1995	21638.29
1996	21868.53
1997	21710.63
1998	22305.25
1999	22686.38
2000	23064.25
2001	23366.67
2002	23688.51
2003	23955.38
2004	24196.18
2005	24416.01
2006	24935.15
2007	25496.78
2008	25997.52
2009	26399.31
2010	26826.22
2011	27170.44
2012	27575.59
2013	27736.98
2014	27377.24
2015	27487.32
2016	27659.56