Year	Number of
1990	139.11
1991	148.02
1992	157.08
1993	165.13
1994	176.29
1995	187.03
1996	195.89
1997	203.05
1998	210.42
1999	215.3
2000	217.86
2001	219.88
2002	220.88
2003	225.17
2004	224.03
2005	225.99
2006	229.89
2007	232.11
2008	235.85
2009	239.82
2010	244.7
2011	250.1
2012	254.81
2013	260.75
2014	266.26
2015	274.57
2016	284.14