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***  Atmospheric Carbon Dioxide Mixing Ratios from the            ***
***  NOAA CMDL Carbon Cycle Cooperative Global Air Sampling       ***
***  Network,  1968-2002                                          ***
***                                                               ***
***  March 2005                                                   ***
***                                                               ***
***  Source: Thomas J. Conway                                     ***
***          Pieter P. Tans                                       ***
***          NOAA Climate Monitoring and Diagnostics Laboratory   ***
***          325 Broadway                                         ***
***          Boulder, Colorado, U.S.A.                            ***
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Year   Jan     Feb     Mar     Apr     May     Jun     Jul     Aug     Sep     Oct     Nov     Dec     Ann

1982  -99.99  -99.99  338.94  338.95  338.88  339.18  339.75  339.95  339.93  339.94  339.96  339.85  -99.99
1983  339.98  340.38  340.60  340.66  340.68  340.99  341.43  341.73  341.82  341.83  341.93  341.92  341.16
1984  342.19  342.47  342.05  341.51  341.46  342.03  342.91  343.10  342.83  342.73  342.91  343.31  342.46
1985  343.41  343.28  343.57  343.71  343.63  343.81  344.15  344.57  344.75  344.84  344.87  344.85  344.12
1986  344.98  345.18  345.17  344.77  344.76  345.23  345.64  345.95  345.98  346.15  346.45  346.48  345.56
1987  346.68  346.70  346.66  346.92  347.13  347.35  347.81  348.48  349.01  349.15  349.21  349.35  347.87
1988  349.25  349.04  348.85  348.80  349.06  349.56  350.07  350.12  350.03  350.06  350.02  349.97  349.57
1989  350.07  350.26  350.29  350.10  349.97  350.34  350.87  351.13  351.25  351.03  351.05  351.34  350.64
1990  351.89  352.39  351.88  351.53  352.15  352.85  353.19  353.39  353.40  353.60  353.77  -99.99  -99.99

Monthly measurements are reported in parts per million (ppm) and are directly traceable to 
the WMO CO2 mole fraction scale. Annual values are the arithmetic means of the 12 monthly values.