What has been the historical carbon dioxide percentage of air over the past 10 000 years?

From 10 000 BC till 1860, the pre-Industrial Age, the carbon dioxide in air was approximately 278 ppm (0.0278%).

In 1900 it was 295 ppm.

In 1960 it was 315 ppm.

In 1980 it was 335 ppm.

In 1990 it was 350 ppm.

In 2000 it was 369 ppm.

In 2010 it was 388 ppm.

In 2011 it was 392 ppm. (March 2011)