The question about the the "White" category always comes up, so here are some of the Census definitions to clarify.
DEFINITION OF WHITE USED IN THE 2010 CENSUS According to OMB, “White” refers to a person having origins in any of the original peoples of Europe, the Middle East, or North Africa. The White racial category includes people who marked the “White” checkbox. It also includes respondents who reported entries such as Caucasian or White; European entries, such as Irish, German, and Polish; Middle Eastern entries, such as Arab, Lebanese, and Palestinian; and North African entries, such as Algerian, Moroccan, and Egyptian.In addition,
Individuals who chose more than one of the six race categories are referred to as the race in combination population, or as the group who reported more than one race. For example, respondents who reported they were White and Black or White and Asian and American Indian and Alaska Native would be included in the White in combination population. This population is also referred to as the multiple-race White population.
In other words, if we include Hispanic/White with White/Alone, the percentage of Whites jumps to 72.4%. In addition, another 2.4% of White in combination with another group is not indicated in the chart. Therefore, the total population who indicated any kind of "White" is 74.8%. Keep in mind that even those Hispanics who identified as Hispanic/White, doesn't mean that they necessarily view themselves as "White." But if the race options on the Census are White, Black or African-American, American Indian or Alaska Native, Asian, or Native Hawaiian or Other Pacific Islander, many Hispanics may elect "White."
We could also reverse that way of thinking and emphasize the Hispanic group. That is, if we combine "Hispanic, White" with "Hispanic, Non-White," Hispanics total 15.7% of the population. More detailed data about Hispanics may be found here.