Approximatly 85% of Broward County is in a Special Flood Hazard Zone, this equals if you have a home or equity loan you will be require to carry a flood insurance policy in these areas, no matter who you are.
see attached link
http://www.co.broward.fl.us/emd/moi00607.pdf
The main factor is how much higher you are than the calculated flood level.
The house that is 1 foot +/- above the calculated flood will pay 50% less,
while a person 1 foot below will pay double or triple.
Palm Beach I have to look for the county map link, I think it is around 50%.