Year	mm Hg
1980	132
1981	131.7
1982	131.3
1983	131
1984	130.8
1985	130.6
1986	130.4
1987	130.1
1988	129.8
1989	129.3
1990	128.8
1991	128.5
1992	128.3
1993	128.1
1994	127.9
1995	127.8
1996	127.8
1997	127.7
1998	127.7
1999	127.7
2000	127.7
2001	127.8
2002	127.9
2003	128
2004	128.2
2005	128.3
2006	128.5
2007	128.7
2008	128.9