Year	Percent
1990	71.452
1991	71.36
1992	71.271
1993	71.146
1994	71.08
1995	71.016
1996	70.952
1997	70.878
1998	70.794
1999	70.704
2000	70.618
2001	70.548
2002	70.481
2003	70.426
2004	70.385
2005	70.356
2006	70.379
2007	70.412
2008	70.455
2009	70.508
2010	70.581
2011	70.682
2012	70.79
2013	70.903
2014	71.007
2015	71.094
2016	71.161
2017	71.233
2018	71.296
2019	71.352
2020	71.4
2021	71.443
2022	71.479
2023	71.513
2024	71.55
2025	71.594
2026	71.643
2027	71.698
2028	71.761
2029	71.833
2030	71.916