Toyota Motor Corporation in Japan announced it has sold four million hybrid vehicles worldwide since the introduction of its first hybrid in 1997. That includes 1.5 million sold in the United States where it holds the largest share of the alternative fuel market.

From that first hybrid 15 years ago, the Toyota line has grown to 18 hybrids sold in 80 countries and regions around the world. This year, Hybrids have made up 15 percent of TMC’s total global vehicle sales.

“All of us at Toyota would like to sincerely thank our customers, who have made Prius the best-selling hybrid in the industry,” said Bob Carter, group vice president and general manager, Toyota Division. “While we’re proud of this accomplishment, we are not stopping here as hybrids will continue to be a core technology for Toyota.”

Toyota estimates that the hybrid vehicles it has sold 1997 have produced approximately 26 million fewer tons of C02 emissions than would have been emitted by gasoline-powered vehicles of similar size and driving performance.