Year	Percent
1990	88.948
1991	88.746
1992	88.737
1993	88.576
1994	88.475
1995	88.437
1996	88.151
1997	88.038
1998	90.608
1999	92.662
2000	94.288
2001	95.565
2002	96.564
2003	97.342
2004	96.649
2005	95.779
2006	94.695
2007	93.347
2008	91.682
2009	89.639
2010	87.155
2011	84.17
2012	80.636
2013	80.537
2014	80.418
2015	80.299
2016	80.243
2017	80.192
2018	80.139
2019	80.086
2020	80.033
2021	79.979
2022	79.925
2023	79.871
2024	79.817
2025	79.764
2026	79.711
2027	79.658
2028	79.607
2029	79.556
2030	79.505