article has more detailed info. Among U.S.-based tech employees the stats are 3% Hispanic and 1% black, vs. 4% and 2% respectively among Facebook's global workforce. 17% of its global tech employees are women.
As one data point of comparison, here
is some demographic data for AP Computer Science test takers in California for the year 2012. Looking at students who take the AP exam may be a good proxy for identifying students who will one day be applying for top-tier positions. Among this group, 7% were Hispanic, 1% were black and 21% were women. If those stats are representative of the pool of top-tier talent in the workforce, then Facebook isn't far off in terms of its hiring of blacks and women. It seems further off with respect to Hispanics. Though, California has a higher-than-usual Hispanic population, so maybe nationally the % of Hispanic AP Exam takers is less than 7.
in USA Today also has some stats. They looked at the demographics of CS and CE graduates from "top" U.S. universities. Not sure what "top" means. They claim that 4.5% of such graduates are black, 6.5% are Hispanic. They didn't report on what % were women.