Medigap Supplement insurance has three rate-pricing alternatives -
community related; issue-age related; and attained-age related.
Pricing varies based on these three factors, inflation and the community/state
of the insured. See much more at
http://www.lucentretirees.com/BenefitsTeam/2008/docs/2009-medigap-medicare.pdf
on page 18 of this Medicare document.