Year	mm Hg
1980	132.6
1981	132.4
1982	132.3
1983	132.1
1984	132
1985	132
1986	131.9
1987	131.9
1988	131.9
1989	131.9
1990	131.8
1991	131.7
1992	131.5
1993	131.4
1994	131.3
1995	131.2
1996	131.2
1997	131.2
1998	131.2
1999	131.2
2000	131.4
2001	131.5
2002	131.7
2003	131.9
2004	132.2
2005	132.4
2006	132.7
2007	133.1
2008	133.5