Year	mm Hg
1980	127.4
1981	127.2
1982	126.9
1983	126.7
1984	126.5
1985	126.3
1986	126.2
1987	126.2
1988	126.2
1989	126.2
1990	126.3
1991	126.3
1992	126.4
1993	126.4
1994	126.4
1995	126.4
1996	126.4
1997	126.4
1998	126.5
1999	126.5
2000	126.6
2001	126.6
2002	126.7
2003	126.9
2004	127.1
2005	127.2
2006	127.3
2007	127.5
2008	127.6