Year	Number of
1990	71.45
1991	71.15
1992	73.42
1993	76.01
1994	76.81
1995	78.49
1996	80.92
1997	83.08
1998	86.72
1999	89.4
2000	90.61
2001	92.25
2002	94.92
2003	98.82
2004	101.2
2005	102.31
2006	103.66
2007	107.07
2008	111.66
2009	115.6
2010	120.81
2011	123.99
2012	126.68
2013	129.48
2014	133.31
2015	137.93
2016	142.51