Year	mm Hg
1980	133.8
1981	133.8
1982	133.8
1983	133.7
1984	133.7
1985	133.6
1986	133.6
1987	133.5
1988	133.5
1989	133.4
1990	133.3
1991	133.1
1992	132.9
1993	132.6
1994	132.3
1995	132
1996	131.8
1997	131.6
1998	131.5
1999	131.5
2000	131.6
2001	131.7
2002	131.9
2003	132.1
2004	132.3
2005	132.4
2006	132.6
2007	132.8
2008	133