Year	Number
1999	28.03857
2000	29.64524
2001	29.2555
2002	29.97956
2003	31.32065
2004	33.05809
2005	33.14305
2006	34.21941
2007	34.45498
2008	36.30997
2009	35.97066
2010	36.37458
2014	35.72074
2016	25.45347
2017	28.42181
2018	28.73155