Each cost of living index is based on a national average of 100. If the amount is below 100, it is lower than the national average. If the amount is above 100, it is higher than the national average. Index: Davenport: Florida: National: Cost of living index: 88: 99: 100: Index: Davenport: Florida: National: Goods & Services index: 94: 99: 100: Groceries index: 100: 102: 100