Year	mm Hg
1980	124.6
1981	124.7
1982	124.8
1983	124.8
1984	124.8
1985	124.8
1986	124.8
1987	124.8
1988	124.8
1989	124.7
1990	124.7
1991	124.7
1992	124.7
1993	124.7
1994	124.7
1995	124.7
1996	124.8
1997	124.8
1998	124.7
1999	124.7
2000	124.7
2001	124.7
2002	124.7
2003	124.6
2004	124.5
2005	124.4
2006	124.2
2007	124.1
2008	123.9