Year	Number of
1990	306.51
1991	312.51
1992	318.47
1993	324.19
1994	331.62
1995	338.59
1996	345.02
1997	351.39
1998	358.19
1999	361.07
2000	365.31
2001	372.48
2002	375.71
2003	382.28
2004	388.8
2005	396.63
2006	402.4
2007	407.89
2008	414.99
2009	422.34
2010	430.69
2011	439.52
2012	452.59
2013	467.17
2014	479.43
2015	493.01
2016	508.92