alder ~ # vnstat -i ppp0 -m

        ppp0

           month        rx      |       tx      |    total
        ------------------------+---------------+---------------
          Jun '06    14,824 MB  |     8,938 MB  |    23,762 MB
          Jul '06    12,427 MB  |     5,414 MB  |    17,842 MB
          Aug '06    20,239 MB  |     5,128 MB  |    25,367 MB
          Sep '06     3,049 MB  |     96.66 MB  |     3,145 MB
        ------------------------+---------------+---------------
        estimated    43,044 MB  |     1,355 MB  |    44,399 MB