Year	Number of
1990	53.84
1991	55.29
1992	56.91
1993	58.69
1994	60.63
1995	62.75
1996	64.04
1997	65.7
1998	67.78
1999	70.74
2000	73.95
2001	76.55
2002	79.29
2003	82.22
2004	85.26
2005	88.52
2006	92.22
2007	96.03
2008	100.28
2009	104.75
2010	109.6
2011	111.85
2012	114.51
2013	117.4
2014	120.55
2015	123.87
2016	127.01