Year	mm Hg
1980	133.4
1981	133.2
1982	133
1983	132.7
1984	132.4
1985	132.2
1986	132
1987	131.9
1988	131.8
1989	131.8
1990	131.7
1991	131.7
1992	131.7
1993	131.7
1994	131.8
1995	131.7
1996	131.8
1997	131.8
1998	131.9
1999	131.9
2000	132
2001	132.1
2002	132.2
2003	132.4
2004	132.6
2005	132.8
2006	133
2007	133.3
2008	133.5