Year	Number of
1990	140.73
1991	150.33
1992	159.41
1993	163.99
1994	165.02
1995	158.51
1996	160.25
1997	159.62
1998	158.03
1999	164.08
2000	162.87
2001	168.86
2002	172.73
2003	177.88
2004	186.65
2005	198.56
2006	207.73
2007	209.72
2008	217.12
2009	222.42
2010	225.26
2011	224.35
2012	219.75
2013	215.63
2014	217.87
2015	223.65
2016	220.33