GMAT Sentence Correction (SC) | Re: Although people in France consume fatty foods at a rate

Hi sayantanc2k, thanks for your help. if you scroll few posts up, experts have said that the following "modified" sentence would be correct:

Although people in France consume fatty foods at a rate comparable to that in the United States, their death rates from heart disease are far lower in France.

My question is: In the above sentence, what would "that" refer to?
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