Year	Number of
1990	294.89
1991	300.01
1992	303.29
1993	312.1
1994	322.13
1995	325.81
1996	328.48
1997	331.85
1998	337.4
1999	349.46
2000	357.93
2001	367.4
2002	373.88
2003	384.71
2004	395.2
2005	405.97
2006	416.49
2007	425.26
2008	436.06
2009	447.45
2010	459.93
2011	473.38
2012	486.58
2013	498.51
2014	511.14
2015	525.2
2016	541.27