(Undated)  --  A new survey shows Seattle and Portland to be among America's "healthiest" cities.  BetterDoctor.com has compiled a ranking of U.S. cities, based on health criteria such as exercise rates, the percentage of highly-rated doctors, and the number of residents with health insurance.  Seattle is ranked ninth in the nation, scoring 57-point-seven on a scale of one to 100.  Portland ranks eleventh with 56-point-seven, while Boston is in first place with a score of 74-point-five.