Year	Number of
1990	100.05
1991	106.32
1992	112.89
1993	120.23
1994	128.17
1995	136.82
1996	146.31
1997	156.65
1998	168.63
1999	181.43
2000	195.06
2001	205.17
2002	215.78
2003	228.02
2004	240.79
2005	254.15
2006	267.05
2007	280.54
2008	295.4
2009	310.91
2010	327.14
2011	340.89
2012	355.19
2013	370.07
2014	385.89
2015	402.76
2016	419.66