Bike share is booming–and it has just hit a major milestone. According to a report published by the Earth Policy Institute, there are over 500,000 bike share bikes in more than 500 cities spread across 49 countries worldwide.

The world’s first bike share bikes hit the streets of Amsterdam in 1965 but very little progress was made in bike share between the 1960s and the 1990s. The majority of growth has occurred in the last two decades, and while Europe has been at the epicenter of that growth, North America is quickly catching up. The continent has 18 new programs slated to touch pavement before the end of this year, growing the total number of programs on the continent by about 50 percent.

“[B]ike sharing has experienced the fastest growth of any mode of transport in the history of the planet,” says transportation advisor and European bike share expert Peter Midgley.

When will the bike share boom plateau? Probably not soon. Given the relative affordability of implementing a program (and we expect it to get cheaper as with the development of any technology) and success of programs around the world, the development of bike share programs will almost certainly be a consistent trend in the coming years, especially in areas with large tourist populations like South America and Southeast Asia.