Year	Number of
1990	30.02
1991	31.61
1992	33.49
1993	35.63
1994	37.81
1995	40.11
1996	41.67
1997	43.05
1998	44.37
1999	46.39
2000	48.44
2001	50.01
2002	52.74
2003	55.73
2004	60.49
2005	66.49
2006	69.5
2007	72.41
2008	77.17
2009	83.26
2010	88.39
2011	93.45
2012	98.04
2013	101.11
2014	104.44
2015	107.78
2016	110.92