Year	mm Hg
1980	131.5
1981	131.3
1982	131.2
1983	131
1984	130.9
1985	130.8
1986	130.7
1987	130.7
1988	130.8
1989	130.9
1990	130.9
1991	131
1992	131.1
1993	131.1
1994	131.1
1995	131.2
1996	131.2
1997	131.2
1998	131.3
1999	131.4
2000	131.6
2001	131.8
2002	132.1
2003	132.4
2004	132.8
2005	133.2
2006	133.6
2007	134
2008	134.4