The U.S. has increased its production of motor vehicles by 5.4 percent, securing the number-two rank behind China on the list of top global auto manufacturers, according to the International Organization of Motor Vehicle Manufacturers (OICA).

Vehicle manufacturers across the country rolled out 6.1 million vehicles in the second quarter of this year, up 3.0 percent from the 5.9 million produced during the same period last year.

A significant percentage of the growth in the U.S. auto industry over the past year is due to increased production by Japanese auto makers, which have invested billions in new assembly plants, research and development centers, and dealerships.

Data shows the companies raised investments in their 26 U.S. manufacturing plants to $40.6 billion in 2013, up from $35.4 billion in 2012, according to the Japan Automobile Manufacturers Association.

In addition, their operations support an estimated 1.52 million private-sector U.S. jobs in 2015, an 11.5 percent increase over the previous year, according to data analyzed by Rutgers University.

Mexico’s automotive industry is also booming. In 2014, Mexican factories produced 3.2 million cars, up 9.8 percent over the previous year with Mexico surpassing Brazil.

Industry analyst AutoForecast Solutions estimates that Big Three automakers GM, Ford and Fiat Chrysler will collectively produce 45 percent of their small cars for the North American market in Mexico by 2020, up from 18 percent in 2014.

GM has invested or plans to invest $5 billion in Mexican plants by 2018. Fiat Chrysler announced more than $1 billion in Mexican plant investments two years ago. In October, 2014, Ford has said it would move its 1.5-liter and 1.6-liter Ford Fiesta engines produced in Mexico, rather than at its plants in Windsor and Essex, Ontario, Canada.

Mexico now ranks as the seventh-largest auto-producing country at a global level. A total production of 3.5 million vehicles is projected for 2015 with analysts also forecasting that production will reach five million cars by 2020, moving the country to fifth rank globally.

The U.S.’s southern NAFTA partner was also the biggest supplier of car parts to the U.S., accounting for 34 percent of 2014 imports, according to OICA.