Year	Number of
1990	104.34
1991	107.59
1992	110.88
1993	113.28
1994	116.03
1995	120.3
1996	124.81
1997	129.3
1998	134.46
1999	135.08
2000	141.81
2001	144.72
2002	144.91
2003	152.89
2004	158.86
2005	164.14
2006	169.52
2007	179.12
2008	190.46
2009	197.05
2010	205.5
2011	217.02
2012	227.15
2013	234.05
2014	241.98
2015	243.85
2016	245.48