Fifteen years ago, an economist from Princeton, Orley Ashenfelter, sought to learn more about the distribution of wealth for McDonalds workers across the world. He used the price of a Big Mac to determine the purchasing power of these workers. He found that most employees wages actually declined due to inflation during the first ten years of his study. Workers in Ireland saw the most income growth throughout the study, while those in Germany actually saw a decline in overall income.
See "Big Mac Test Shows Job Market Is Not Working to Distribute Wealth", Eduardo Porter, The New York Times, April 22, 2015