Year	mm Hg
1980	127.8
1981	127.7
1982	127.6
1983	127.4
1984	127.3
1985	127.1
1986	126.9
1987	126.8
1988	126.7
1989	126.6
1990	126.4
1991	126.3
1992	126.2
1993	126.2
1994	126.1
1995	126.1
1996	126
1997	126
1998	126
1999	126
2000	126.1
2001	126.2
2002	126.3
2003	126.4
2004	126.5
2005	126.7
2006	126.8
2007	126.9
2008	127.1