The National Opinion Research Center(NORC) in Chicago is a credible organization and conducts valid research in many areas. I was one of the early users of their statistical program package(SPSS) way back in the 1970s when I worked in the Research Department of my University.
Having said that; I suspect their percentages of firearms ownership is being under reported. A respondent in Chicago,for example, would probably say NO even if they owned a handgun because even after the Supreme Court ruled McDonald vs. Chicago
that their handgun ban was unconstitutional the City has done everything possible to circumvent it.
The Police Department in Phoenix,AZ issued a report a couple of years ago stating the 60% of the cars there contained a firearm*.
They estimate that upwards of 70% of the homes** contain at least 1 firearm.
*This is probably the reason car jackings are rare here.
**Occupied home breakins are also rare here unless they are drug or gang related or both.
Jim
