CONTEXT

For those that don't know, the methodology used in the US Census is intentionally flawed and designed to fracture various "white" groups in order to lower the "official" percentage of the white population. Most Hispanics should be, and traditionally were (since the early 1900s) included in the white demographic. The same is also true of the "two or more races" category, which likewise was created to further fragment the white demographic on "official" paper statistics.

If you account for both of these factors and/or use self identification, it's generally accepted that the US is roughly 75-80% white when you get rid of the intentional demographic fragmentation and account for racial self identification (Depending on the source you find, anywhere from 52%-60% of hispanics identify as white, and roughly 48-54% of all "mixed race" people identify as white in day to day life.)

Of course if you wanted to get a clearer picture then you'd have to get rid of the illegals, but that's where things get complicated since there's basically no way of determining what percentage of illegals actually answer census questions. But I think that, generally speaking, that 75-80% figure is probably an accurate range even if you deport all the illegals.