Year	Number of
1990	72.46
1991	76.24
1992	80.24
1993	84.56
1994	89.21
1995	94.09
1996	99.21
1997	104.42
1998	109.86
1999	115.64
2000	122.67
2001	132.43
2002	142.65
2003	153.3
2004	164.75
2005	177.35
2006	186.38
2007	196.87
2008	208.37
2009	220.75
2010	233.32
2011	242.18
2012	246.32
2013	250.31
2014	254.45
2015	258.75
2016	264.64