Year	Number of
1990	120.68
1991	126.18
1992	132.89
1993	139.36
1994	146.74
1995	153.36
1996	158.26
1997	164.57
1998	169.96
1999	172.48
2000	177.58
2001	183.27
2002	193.76
2003	196.14
2004	197.66
2005	200.43
2006	203.45
2007	208.15
2008	214.98
2009	223.59
2010	234.76
2011	247.29
2012	258.79
2013	271.05
2014	284.78
2015	299.72
2016	321.57