Year	Number of
1990	124.1
1991	130.63
1992	131.48
1993	136.15
1994	136.05
1995	132.76
1996	129.48
1997	131.68
1998	132.49
1999	134.17
2000	141.73
2001	146.82
2002	148.37
2003	154.23
2004	159.75
2005	167.65
2006	168.87
2007	170.13
2008	171.17
2009	171.14
2010	169.45
2011	184.88
2012	196.89
2013	208.6
2014	214.86
2015	216.82
2016	221.63