Year	Number of
1990	77.79
1991	80.37
1992	83.12
1993	86
1994	88.95
1995	91.94
1996	94.2
1997	96.42
1998	98.67
1999	101.03
2000	103.6
2001	105.83
2002	108.23
2003	110.83
2004	113.58
2005	116.46
2006	119.46
2007	122.59
2008	126.01
2009	129.66
2010	133.61
2011	137.75
2012	142.16
2013	146.7
2014	151.59
2015	156.86
2016	162.63