Year	mm Hg
1980	134.3
1981	134
1982	133.7
1983	133.5
1984	133.2
1985	133
1986	132.8
1987	132.7
1988	132.4
1989	132.3
1990	132.1
1991	131.9
1992	131.8
1993	131.6
1994	131.4
1995	131.3
1996	131.2
1997	131.1
1998	131
1999	131
2000	131.1
2001	131.2
2002	131.3
2003	131.5
2004	131.7
2005	132
2006	132.3
2007	132.6
2008	133