Year	Percent
1990	80.465
1991	80.428
1992	80.409
1993	80.25
1994	79.999
1995	79.693
1996	79.702
1997	79.55
1998	79.37
1999	79.168
2000	79.015
2001	79.042
2002	79.002
2003	79.026
2004	78.881
2005	78.792
2006	78.954
2007	79.064
2008	79.142
2009	79.146
2010	79.046
2011	79.428
2012	79.685
2013	80.401
2014	80.418
2015	80.277
2016	79.93
2017	79.956
2018	79.984
2019	80.021
2020	80.077
2021	80.239
2022	80.434
2023	80.653
2024	80.889
2025	81.137
2026	81.408
2027	81.684
2028	81.964
2029	82.248
2030	82.536