Year	Number of
1990	91.62
1991	97.48
1992	103.48
1993	110.27
1994	116.94
1995	123.51
1996	128.71
1997	133.96
1998	137.44
1999	140.82
2000	144.48
2001	148.18
2002	152.03
2003	156.5
2004	161.24
2005	166.29
2006	170.72
2007	175.67
2008	181.15
2009	187.2
2010	193.69
2011	200.19
2012	207.47
2013	214.98
2014	223.14
2015	232.54
2016	242.91