Marsh 12Z msl_pressure 1987 - - - - - - - - - - - - 1988 - - - - - - - - - 1000.6 - - 1989 991.8 - - 991.7 - - 995.5 - - 984.3 985.4 - 1990 - - - - 1004.0 - - - 994.1 977.8 - - 1991 988.3 - 990.6 992.8 - - - - - - - - 1992 - - - - - - - - - - - - 1993 - - - - - - - - - 985.7 986.1 984.8 1994 - - 994.5 995.6 - 997.2 994.6 989.7 982.1 989.7 994.4 - 1995 - - - 992.3 - 990.1 989.9 995.2 - 994.0 983.2 988.0 1996 991.7 - - 996.1 988.0 993.5 992.0 989.8 - 984.9 976.6 - 1997 988.8 994.2 990.0 985.8 - - - - 994.7 991.3 - - 1998 985.8 - 990.6 996.8 - 996.8 979.4 986.1 990.1 981.8 984.9 983.4 1999 990.2 984.7 996.3 989.3 992.2 997.8 990.5 990.0 992.3 985.7 987.7 983.7 2000 981.8 995.9 1002.0 988.4 - 998.3 1005.1 992.6 1002.5 988.7 995.8 989.3 2001 988.8 988.1 - 987.4 999.1 992.7 - 982.3 991.8 985.6 - 983.7 2002 - 987.9 991.9 - 993.8 991.3 995.3 999.1 1002.7 989.5 990.8 990.3 2003 993.1 987.2 997.6 994.2 991.4 996.8 984.7 - - 984.9 984.5 998.2 2004 986.7 998.2 989.5 992.2 992.9 988.8 991.3 992.5 979.6 - - 991.9 2005 986.9 987.0 991.5 984.2 994.7 996.5 997.6 992.7 999.3 993.9 991.2 994.9 2006 - - 982.4 992.5 - - - 999.9 992.6 - 983.0 985.7 2007 990.8 987.7 989.7 - - - 995.1 986.8 997.7 983.3 990.8 985.1 2008 987.3 989.8 991.2 987.3 993.8 993.6 994.6 991.3 1000.7 - 984.3 982.1 2009 985.8 - - - - - - - - - - -