Year	%
1981	13.704070595439
1982	13.704070595439
1983	13.704070595439
1984	14.055457020963
1985	14.7582298720112
1986	14.7582298720112
1987	12.2106782869616
1988	10.9808257976274
1989	10.5415927657223
1990	11.2882889199609
1991	11.9059743876173
1992	12.810449932971
1993	11.8140626868538
1994	11.0596618309
1995	12.6827484777444
1996	12.8214561836334
1997	12.6817721325456
1998	11.4038205442493
1999	12.7914768846466
2000	13.0629574857111
2001	12.9728682897903
2002	12.5874972528272
2003	14.9972422139427
2004	11.0707816198869
2005	10.6053045549906
2006	10.7839950834178
2007	10.1219067962335
2008	10.0849310391437
2009	10.5820111235866
2010	10.6165388642549
2011	10.0020504342406
2012	9.50031901972522
2013	9.07521429780519
2014	8.99774238858608
2015	8.85541666666667
2016	8.4725
2017	8.34
2018	8.11011591666667
2019	7.72247983333333
2020	7.13469175
2021	6.75742416666667
2022	6.5128745
2023	6.40448225