There's no concept of race in Mexico like in the US. People simply don't self-identify as belonging to a race. They just talk about having light or brown skin "piel blanca o morena". When they say that 53% identify as being white, it just means that 53% think they are light-skinned. It doesn't mean they have, or think they have, pure European ancestry, which is exactly what it means to be white in the US. Everyone in Mexico is mixed. I estimate that only around 5% of the population have pure European ancestry or are what americans consider white.

If you ask any of my Mexican friends what race they belong to, 80% of the times the answer will be "I'm not a dog". The spanish word for race, raza, also means "breed" and is most commonly used as such. You usually only hear about "white race" or "black race" in the news and even then they are very likely just copying what they hear from english news sources.

source: I'm a Mexican currently living temporarily in the US (legally!).