Year	Number of
1990	69.05
1991	74.97
1992	81.95
1993	90.2
1994	99.98
1995	111.58
1996	121.27
1997	132.05
1998	143.72
1999	156.41
2000	170.76
2001	184.96
2002	201.01
2003	221.05
2004	248.09
2005	284.61
2006	316.94
2007	360.04
2008	411.58
2009	467.55
2010	525.38
2011	594.18
2012	662.16
2013	731.13
2014	805.26
2015	888.77
2016	972.69