Year	mm Hg
1980	129.7
1981	129.7
1982	129.7
1983	129.7
1984	129.7
1985	129.7
1986	129.8
1987	129.9
1988	130.1
1989	130.2
1990	130.4
1991	130.6
1992	130.7
1993	130.8
1994	130.9
1995	131
1996	131.1
1997	131.1
1998	131.3
1999	131.5
2000	131.7
2001	132
2002	132.4
2003	132.8
2004	133.2
2005	133.7
2006	134.1
2007	134.6
2008	135.1