Year	Number of
1990	151.26
1991	154.73
1992	159.69
1993	166.32
1994	173.41
1995	180.67
1996	188.62
1997	196.62
1998	205.19
1999	214.21
2000	223.95
2001	231.71
2002	240.03
2003	249.21
2004	258.7
2005	268.54
2006	278.99
2007	289.76
2008	301.53
2009	313.83
2010	326.82
2011	337.6
2012	348.92
2013	360.36
2014	372.45
2015	385.21
2016	400.59