The Mexican government has implemented a new tax on sodas that has caused sugary drinks to dive by 12 percent.

At the same time, bottled water sales have risen 4 percent, and observers are already hailing the soda tax as a huge success, according to a New York Times report.

It’s the first hard evidence that such a soda tax can actually change the behavior of individuals, and it could encourage other countries to enact similar policies.

Franco Sassi, who is the head of the public health program at the think tank Organization for Economic Cooperation and Development in Paris, said that this was incredibly encouraging news that unhealthy behavior can be curbed.

“There are many countries in the region and other parts of the world that have been waiting on empirical evidence from Mexico to determine whether to implement similar measures,” he said according to the report. “I think this is encouraging for all the countries that have been deciding whether to use this measure. This is a demonstration that it works.”

Like many other countries, Mexico struggles with obesity. However, Mexico has a particularly big problem with it, ranking No. 1 among the 34 developed countries that are members of the OECD. About 70 percent of adults are overweight or obese, and the country has the highest rate of Type 2 diabetes.

It was this situation that prompted Mexican officials to enact the soda tax. The food and beverage industry certainly didn’t like the tax and fought it tooth and nail, but the Mexican government eventually passed the tax in January of 2014. As a result of the tax, the cost of soft drinks rose 10 percent.