27 Billion Tons of CO2? No, I don't think so!

This an email that I sent to the USGS (US Geologic Survey) to let them know of this mistake I found concerning the 27 Billion tons of CO2 supposedly being dumped in to the air by us humans every year. If you can find where I can see an actual report or paper showing that we do this I will write an apology.

Dear Sir:
I am concerned that a mistake in the article on Volcanic Hazards http://volcanoes.usgs.gov/Hazards/What/VolGas/volgas.html#reference has created a wide spread misunderstanding in regards to the amount of CO2 released by man into the atmosphere each year. Here in the article you will see the reference to the 27 Billion tons of CO2 released;

From "Volcanic Gases and Their Effects"

Comparison of CO2 emissions from volcanoes vs. human activities.Scientists have calculated that volcanoes emit between about 130-230 million tonnes (145-255 million tons) of CO2 into the atmosphere every year (Gerlach, 1999, 1991). This estimate includes both subaerial and submarine volcanoes, about in equal amounts. Emissions of CO2 by human activities, including fossil fuel burning, cement production, and gas flaring, amount to about 27 billion tonnes per year (30 billion tons) [ ( Marland, et al., 2006) - The reference gives the amount of released carbon (C), rather than CO2, through 2003.]. Human activities release more than 130 times the amount of CO2 emitted by volcanoes--the equivalent of more than 8,000 additional volcanoes like Kilauea (Kilauea emits about 3.3 million tonnes/year)! (Gerlach et. al., 2002)

Then there is a footnote, (Marland, et al., 2006) I saw the link (http://cdiac.ornl.gov/trends/emis/meth_reg.htm) , and went there. Seeing nothing that stated 27 Billion tons of carbon released I proceeded to the bottom of the page and linked to the CDIAC page http://cdiac.ornl.gov/trends/emis/em_cont.htm , which lead me to the "On Line Trends" page. I looked under the global http://cdiac.ornl.gov/trends/emis/tre_glob.htm , and Keoto page http://cdiac.ornl.gov/trends/emis/annex.htm and only found information that would lead me to see that only 7.9 Gt of CO2 were released. This is too much, but nothing like the 27Gts that is stated in the above reference article.
Please tell me where the "27 billion tonnes per year" comes from. As you can see, the paragraph is not structured well and can create confusion. Look at the sentence right after the highlighted segment. "The reference gives the amount of released carbon (C), rather than CO2, through 2003'. Does this mean that the 27 Billion tonnes is what was released up through 2003, meaning including all the years hence? Or just for 2003. If it is just 2003, it flies in the face of the IPCC and Keoto numbers of 5Gts to 8Gts.
Where did the 27 billion come from, I see no reference to it in any footnoted article or in any of my research?
Please respond as soon as you are able. Thank you for your time and efforts.