Year	mm Hg
1980	130.7
1981	130.6
1982	130.5
1983	130.5
1984	130.4
1985	130.4
1986	130.4
1987	130.4
1988	130.5
1989	130.6
1990	130.7
1991	130.8
1992	130.9
1993	131
1994	131.2
1995	131.3
1996	131.5
1997	131.7
1998	131.9
1999	132.1
2000	132.4
2001	132.8
2002	133.1
2003	133.5
2004	133.8
2005	134.2
2006	134.7
2007	135.1
2008	135.6