Year	mm Hg
1980	127.5
1981	126.9
1982	126.4
1983	126
1984	125.7
1985	125.5
1986	125.3
1987	125.2
1988	125.2
1989	125.2
1990	125.2
1991	125.3
1992	125.4
1993	125.5
1994	125.6
1995	125.8
1996	126
1997	126.2
1998	126.4
1999	126.7
2000	127
2001	127.3
2002	127.6
2003	127.8
2004	128
2005	128.2
2006	128.4
2007	128.6
2008	128.7