Year	Percent
1990	38.739
1991	38.879
1992	39.083
1993	39.213
1994	39.402
1995	39.734
1996	39.827
1997	40.124
1998	40.526
1999	40.828
2000	41.081
2001	41.289
2002	41.598
2003	41.792
2004	42.092
2005	44.441
2006	46.834
2007	45.567
2008	44.28
2009	42.986
2010	41.711
2011	40.456
2012	46.296
2013	40.685
2014	40.9
2015	39.115
2016	40.629
2017	40.631
2018	40.632
2019	40.636
2020	40.649
2021	40.676
2022	40.711
2023	40.746
2024	40.772
2025	40.782
2026	40.784
2027	40.773
2028	40.75
2029	40.719
2030	40.685