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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

1968  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  -99.99  324.13  324.80  -99.99
1969  325.73  326.52  326.94  327.85  328.42  325.15  320.76  318.04  318.41  321.06  323.67  325.79  324.03
1970  327.88  329.22  330.44  330.79  328.99  326.09  322.48  319.82  321.08  324.79  327.23  327.70  326.38
1971  328.96  331.15  331.52  331.13  329.97  326.89  322.57  319.01  319.62  324.18  327.29  329.44  326.81
1972  331.13  330.99  331.42  333.14  332.17  326.66  321.04  319.53  320.71  325.18  328.49  330.02  327.54
1973  331.77  332.75  333.66  334.67  334.22  -99.99  -99.99  -99.99  -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.