Year	mm Hg
1980	128.2
1981	128.2
1982	128.2
1983	128.1
1984	128.1
1985	128.1
1986	128.2
1987	128.2
1988	128.3
1989	128.3
1990	128.3
1991	128.3
1992	128.3
1993	128.3
1994	128.3
1995	128.3
1996	128.3
1997	128.3
1998	128.3
1999	128.3
2000	128.3
2001	128.4
2002	128.4
2003	128.4
2004	128.5
2005	128.7
2006	128.9
2007	129.1
2008	129.3