Year	Number of
1990	91.02
1991	90.03
1992	90.47
1993	90.97
1994	91.73
1995	93.09
1996	95.76
1997	96.62
1998	102.01
1999	106.29
2000	110.54
2001	110.82
2002	112.71
2003	118.6
2004	126.03
2005	133.55
2006	142.95
2007	151.04
2008	157.47
2009	164.5
2010	170.29
2011	176.11
2012	186.62
2013	197.14
2014	208.1
2015	218.4
2016	228.06