Detroit, Michigan - Almost six months after Donald Trump was sworn in as president and threatened to penalize automakers who import cars and trucks from Mexico, the flow of vehicles from south of the border has picked up momentum.

New data from the Mexican Automobile Industry Association shows the country exported 1.16 million vehicles to the U.S. in the first half of 2017, an increase of 15.6 percent compared with the same time frame in 2016.

Not only that, the U.S. has taken on a greater percentage of the total number of vehicles exported from Mexico to markets around the world. In the first half of the year, 76.8% of all cars and trucks shipped out of Mexico went to the U.S., that is up almost a full percentage point compared with a year ago.

In January, Trump tweeted, "The U.S. has a 60 billion dollar trade deficit with Mexico. It has been one-sided deal from the beginning of NAFTA with massive numbers of jobs and companies lost."

The increase in imports comes as U.S. auto sales have slowed down in 2017, falling 2.1%.

While Trump was able to pressure Ford to stop building a final assembly plant in Mexico, his efforts to slow down the flow of autos from Mexico have been mixed.

When asked recently by CNBC if he plans to halt plans to build a final assembly plant in Mexico, the chairman of BMW said no changes are planned. That plant is scheduled to open in 2019.

In the first half of this year, total auto production in Mexico surged 12.6 percent to an all-time high of 1.88 million vehicles.