Year	mm Hg
1980	131.6
1981	131.3
1982	130.9
1983	130.6
1984	130.2
1985	129.8
1986	129.6
1987	129.4
1988	129.2
1989	129.2
1990	129.1
1991	129
1992	129
1993	128.9
1994	128.8
1995	128.8
1996	128.7
1997	128.6
1998	128.5
1999	128.4
2000	128.3
2001	128.2
2002	128.1
2003	128
2004	127.9
2005	127.9
2006	127.9
2007	127.8
2008	127.7