Year	Percent
1990	59.5
1991	60.263
1992	60.944
1993	61.825
1994	62.453
1995	61.452
1996	60.109
1997	58.509
1998	56.64
1999	56.266
2000	55.868
2001	55.688
2002	55.53
2003	55.413
2004	55.398
2005	55.643
2006	55.906
2007	56.072
2008	56.119
2009	56.002
2010	56.059
2011	56.236
2012	56.315
2013	56.46
2014	56.602
2015	56.733
2016	57.02
2017	57.294
2018	57.562
2019	57.785
2020	57.937
2021	58.096
2022	58.19
2023	58.227
2024	58.229
2025	58.207
2026	58.237
2027	58.257
2028	58.241
2029	58.152
2030	57.97