Year	Number
1996	21.1055278778076
1998	24.5
2000	26.3681583404541
2002	20.3980102539063
2003	25.3731346130371
2004	23.0769233703613
2005	23.4449768066406
2006	29.6650714874268
2007	29.6650714874268
2008	31.25
2009	30.8056869506836
2010	28.9099521636963
2011	31.4553985595703
2012	31.9248828887939
2013	32.3943672180176
2014	27.4038467407227
2015	29.5238094329834
2016	31.4285717010498
2017	31.4285717010498
2018	31.9047622680664
2019	30.4761905670166
2020	31.4285717010498
2021	30
2022	30.1886787414551