Year	Number of
1990	61.69
1991	64.32
1992	67.53
1993	71.09
1994	74.49
1995	78.18
1996	81.06
1997	83.74
1998	86.72
1999	90.03
2000	93.04
2001	94.85
2002	96.59
2003	98.75
2004	101.26
2005	103.64
2006	105.65
2007	108.09
2008	110.8
2009	113.87
2010	117.19
2011	119.79
2012	122.8
2013	125.86
2014	129.64
2015	134.02
2016	137.99