Year	Percent
1990	66.381
1991	66.353
1992	66.071
1993	65.896
1994	65.829
1995	65.725
1996	66.029
1997	67.19
1998	67.586
1999	67.929
2000	68.533
2001	68.397
2002	68.367
2003	67.86
2004	67.911
2005	67.909
2006	67.891
2007	67.907
2008	67.905
2009	67.946
2010	68.12
2011	68.32
2012	68.579
2013	68.919
2014	69.214
2015	69.542
2016	69.839
2017	69.915
2018	69.99
2019	70.056
2020	70.112
2021	70.158
2022	70.195
2023	70.226
2024	70.253
2025	70.279
2026	70.302
2027	70.325
2028	70.349
2029	70.378
2030	70.413