Year	Number of
1990	277.26
1991	281.77
1992	288.51
1993	300.14
1994	313.94
1995	330.32
1996	343.96
1997	357.35
1998	373.86
1999	369.82
2000	374.02
2001	376.51
2002	397.15
2003	419.01
2004	431.52
2005	451.49
2006	470.38
2007	483.31
2008	504.06
2009	527.67
2010	551.03
2011	572.23
2012	598.06
2013	615.15
2014	637.32
2015	659.47
2016	683.63