Year	Number of
1990	211.51
1991	214.84
1992	218.77
1993	223.63
1994	227.89
1995	233.04
1996	238.05
1997	245.03
1998	254.19
1999	259.87
2000	269.18
2001	275.31
2002	281.87
2003	292.63
2004	302.99
2005	313.06
2006	324.57
2007	336.25
2008	347.58
2009	358.47
2010	376.65
2011	392.17
2012	410.23
2013	429.71
2014	446.4
2015	462.56
2016	485.83