Toyota is rightfully celebrating this week with the announcement that it has sold four million hybrids around the world since the first one launched in Japan in 1997. Not a bad effort.

More impressive is that the last million of those were sold in just 14 months, which is especially interesting given it took the company 10 years to sell the first million.

The number does include Lexus hybrids, which could be considered as cheating to get to the four million mark. It’s forgivable though, given that the number is mostly made up by the Prius, with over 2.6-million sold.

The Japanese auto company is also looking to sell a million hybrids in a calendar year for the first time in 2012, with 425,000 sold in the first four months of the year.

So all-in-all, the hybrid market is working pretty well for Toyota. I wonder if full electric vehicles will be enjoying the same level of success in 15 years?