This page of data links was started to help you find the source dataset you are looking for.
CO2 Data | Years 0 to 2014
Datasets are compiled by the Institute for Atmospheric and Climate Science (IAC) at Eidgenössische Technische Hochschule in Zürich, Switzerland.
IAC Switzerland Global CO2 Yearly [excel]
IAC Switzerland Global CO2 Monthly [excel]
CO2 Data Pages
More Data and Info
NOAA-NCDC Paleoclimate datasets