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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

1979  -99.99  -99.99  339.23  340.49  340.59  339.10  335.06  332.48  333.36  334.72  336.25  337.65  -99.99
1980  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  335.42  335.93  338.05  339.91  -99.99
1981  341.13  341.90  342.80  343.77  343.19  342.13  340.59  337.90  336.42  336.89  338.21  339.95  340.41
1982  341.95  343.01  343.25  343.77  343.94  343.15  340.78  337.49  336.39  337.63  339.32  341.06  340.98
1983  341.97  342.88  344.60  344.90  344.17  344.62  342.50  339.14  339.64  339.79  338.86  340.52  341.97
1984  343.34  344.61  345.54  347.01  347.91  346.93  343.59  339.86  338.56  339.54  341.06  343.38  343.44
1985  345.49  345.90  346.46  347.65  348.50  348.17  345.81  343.22  342.10  342.33  344.13  345.81  345.46
1986  346.53  347.59  348.76  349.22  349.52  349.14  346.91  344.13  343.02  343.88  345.72  347.02  346.79
1987  347.87  349.27  350.75  351.46  350.74  349.49  348.15  346.67  345.60  345.59  347.14  348.97  348.48
1988  350.48  351.77  353.01  353.98  354.59  353.77  350.96  348.74  348.38  349.07  350.55  352.09  351.45
1989  353.31  354.02  354.74  355.92  356.66  355.59  353.36  351.34  350.46  350.82  352.15  353.88  353.52
1990  354.74  355.67  356.69  357.40  357.71  357.13  354.69  351.57  -99.99  -99.99  -99.99  -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.