Year	Percent
1990	80.805
1991	80.529
1992	81.101
1993	81.487
1994	80.803
1995	81.532
1996	80.674
1997	81.005
1998	80.505
1999	80.554
2000	80.543
2001	80.179
2002	80.187
2003	79.917
2004	79.828
2005	79.509
2006	79.272
2007	79.328
2008	79.167
2009	79.322
2010	79.463
2011	79.506
2012	78.907
2013	78.89
2014	78.911
2015	78.711
2016	78.819
2017	78.849
2018	78.858
2019	78.85
2020	78.827
2021	78.825
2022	78.812
2023	78.782
2024	78.725
2025	78.64
2026	78.564
2027	78.462
2028	78.347
2029	78.24
2030	78.153