The Journal of the American Medical Association published a study on sales of sugar-sweetened and artificially sweetened beverages following Philadelphia's implementation of a tax on them in January 2017. It found that the total volume of sales of taxed beverages in Philadelphia decreased by 51 percent in the year following the implementation of the tax, but sales just outside of Philadelphia increased by 308.2 million ounces, according to the study. The study also compared sales data from Philadelphia and the surrounding area zip codes with Baltimore, MD, which does not have a soda tax.