The numbers are too good to be true.
I don't have a counter-survey to provide you to prove my "gut feeling" and anecdotal from my personal experience, I might hang out with all the unprepared people in the nation, but — I think not.
People have a tendency to overstate their level of disaster preparedness. I just don't see how that high a percentage of people can really be prepared. If you told me the nation surveyed was Japan, I'd be more likely to believe the numbers.
You make your own assessment and tell me what you think. Maybe I'm too pessimistic in my thinking. Email me at firstname.lastname@example.org