Year	Number
1973	42.21245
1993	43.27474
2001	24.80491
2002	23.01843
2007	25.54864
2008	27.80707
2009	24.59079
2010	25.49121
2011	25.03079
2012	25.68275
2013	25.71434
2014	24.57417
2015	23.28667