Year	Number of
1990	55.03
1991	56.73
1992	58.6
1993	60.39
1994	62.44
1995	64.75
1996	66.69
1997	68.76
1998	71.12
1999	73.51
2000	75.95
2001	78.06
2002	80.18
2003	82.84
2004	85.6
2005	88.52
2006	89.3
2007	90.15
2008	91.16
2009	92.29
2010	93.61
2011	96.02
2012	98.66
2013	101.43
2014	104.27
2015	107.14
2016	110.3