All of that data is based on ice cores.

Here is more from NOAA:
http://www.ncdc.noaa.gov/paleo/globalwarming/home.html

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine