Year	Number of
1990	222.31
1991	218.59
1992	205.97
1993	190.04
1994	170.29
1995	160.84
1996	158.56
1997	162.77
1998	163.43
1999	165.64
2000	173.03
2001	176.37
2002	185.05
2003	199.25
2004	212.84
2005	208.09
2006	190.64
2007	178.65
2008	186.54
2009	190.77
2010	193.36
2011	191.7
2012	190.33
2013	187.73
2014	185.83
2015	183.47
2016	181.45