Year	mm Hg
1980	139.5
1981	138.8
1982	138.2
1983	137.5
1984	136.8
1985	136.1
1986	135.4
1987	134.8
1988	134.2
1989	133.7
1990	133.2
1991	132.7
1992	132.2
1993	131.8
1994	131.4
1995	131
1996	130.6
1997	130.2
1998	129.9
1999	129.5
2000	129.2
2001	128.9
2002	128.5
2003	128.2
2004	127.8
2005	127.4
2006	127.1
2007	126.7
2008	126.3