Year	mm Hg
1980	130.2
1981	130.2
1982	130.1
1983	129.9
1984	129.9
1985	129.8
1986	129.7
1987	129.7
1988	129.7
1989	129.7
1990	129.7
1991	129.8
1992	129.9
1993	130
1994	130.1
1995	130.2
1996	130.4
1997	130.6
1998	130.9
1999	131.3
2000	131.7
2001	132.1
2002	132.6
2003	133.1
2004	133.7
2005	134.3
2006	135
2007	135.6
2008	136.3