Year	Number of
1990	253.58
1991	254.16
1992	255.33
1993	258.52
1994	262.62
1995	265.75
1996	271.88
1997	281.67
1998	268.29
1999	267.07
2000	258.35
2001	250.52
2002	245.81
2003	239.33
2004	233.84
2005	232.81
2006	228.44
2007	220.04
2008	218.03
2009	219.89
2010	222.6
2011	226.8
2012	229
2013	228.06
2014	225.35
2015	222.61
2016	223.08