Year	Percent
1990	3.405
1991	3.413
1992	3.419
1993	3.427
1994	3.416
1995	3.409
1996	3.407
1997	3.402
1998	3.389
1999	3.392
2000	3.383
2001	3.376
2002	3.364
2003	3.362
2004	3.355
2005	3.345
2006	3.336
2007	3.319
2008	3.315
2009	3.332
2010	3.328
2011	3.317
2012	3.308
2013	3.302
2014	3.293
2015	3.28
2016	3.275
2017	3.269
2018	3.264
2019	3.258
2020	3.253
2021	3.247
2022	3.242
2023	3.236
2024	3.23
2025	3.225
2026	3.219
2027	3.214
2028	3.208
2029	3.203
2030	3.197