Regional totals;Period;Total
National Total;2024;31.30
National Total;2023;30.91
National Total;2022;30.68
National Total;2021;30.15
National Total;2020;29.92
National Total;2019;29.70
National Total;2018;29.41
National Total;2017;29.00
National Total;2016;28.59
National Total;2015;28.18
National Total;2014;27.53
National Total;2013;26.67
National Total;2012;26.06
National Total;2011;25.55
National Total;2010;24.94
National Total;2009;24.46
National Total;2008;24.19
National Total;2007;24.36
National Total;2006;24.52
National Total;2005;24.37
National Total;2004;24.82
National Total;2003;25.12
National Total;2002;25.24
National Total;2001;24.89
National Total;2000;24.51
National Total;1999;24.17
National Total;1998;23.74
National Total;1997;23.28
National Total;1996;22.91
National Total;1995;22.48
National Total;1994;22.13
National Total;1993;21.78
National Total;1992;21.49
National Total;1991;21.16
National Total;1990;20.76
National Total;1989;20.34
National Total;1988;19.93
National Total;1987;19.47
National Total;1986;19.11
National Total;1985;18.81
National Total;1984;18.69
National Total;1983;18.57
National Total;1982;18.46
National Total;1981;18.34
National Total;1980;18.14
National Total;1979;17.89
National Total;1978;17.65
National Total;1977;17.36
National Total;1976;17.15
National Total;1975;16.82