Year	mm Hg
1980	127.3
1981	127.2
1982	127
1983	126.8
1984	126.6
1985	126.4
1986	126.2
1987	126
1988	125.9
1989	125.8
1990	125.8
1991	125.9
1992	125.9
1993	125.9
1994	126
1995	126.1
1996	126.2
1997	126.3
1998	126.4
1999	126.4
2000	126.5
2001	126.6
2002	126.7
2003	126.8
2004	126.9
2005	126.9
2006	126.9
2007	126.9
2008	126.9