比较两个城市之间的生活成本差异，并计算出要在新城市维持当前生活水平所需的薪水。
You can find Cost of Living Index data on websites like Numbeo or PayScale. The national average is typically benchmarked at 100. A city with an index of 120 is 20% more expensive than the average, while a city with an index of 90 is 10% cheaper.