Hey
blades19GREAT question, and unfortunately, I don't think there's a clear answer or a number you can put on things. Underrepresented minorities still need to put together ace applications -- the whole package needs to be there: GMAT, GPA, work experience, extracurriculars, etc.
Now, what is great though is that there are additional resources available to you. URMs in the US should sign up with The Consortium and consider applying through there. Also, many programs have Hispanic Student Groups that both formally and informally are involved in the admissions process. Before you prep your apps, reach out to these clubs/groups and ask them about special admissions events that you could attend or if there's any sort of mailing list you can be added to. One of my clients a few years back got invited to Wharton's diversity event and had a great time -- he also got some great tips for his app.
I hope that helps!
Krista