Year	Number
1996	15.7608699798584
1998	14.6739130020142
2000	13.043478012085
2002	18.3783779144287
2003	15.1351346969604
2004	14.4278602600098
2005	12.2549018859863
2006	15.1960783004761
2007	18.4466018676758
2008	20.3883495330811
2009	24.8803825378418
2010	26.3157901763916
2011	28.4360198974609
2012	29.3838863372803
2013	29.8578205108643
2014	31.730770111084
2015	31.9047622680664
2016	28.5714282989502
2017	29.5238094329834
2018	35.238094329834
2019	33.3333320617676
2020	32.3809509277344
2021	31.9047622680664
2022	31.6037731170654