Investing in fast-growing industries is like sailing with the wind at your back.

When a sector is young and vibrant, opportunities for ambitious entrepreneurs are practically limitless.

And as regular readers know, marijuana is among the fastest-growing sectors in North America.

To review, the legal cannabis sector grew from $1.5 billion in 2013 to $2.7 billion in 2014, an increase of 74%. It’s expected to grow another 68% through 2015. That’s according to ArcView, a widely respected marijuana research firm.

The Washington Post reports that legal marijuana sales could top $35 billion by 2020.

My point is simple. Billion-dollar industries growing this fast don’t come along very often. It’s even rarer to find one with a clear path to continued growth for the foreseeable future.

But that’s exactly what we’re seeing with cannabis today.

In Oregon, for example, there are already more pot shops than Starbucks or McDonald’s.

Meanwhile, Colorado’s government will collect around $125 million in marijuana taxes this year (more than it’ll collect on alcohol).

Another six states will vote to legalize recreational marijuana use next year, says Fortune.

And in total, 23 U.S. states plus Washington, D.C., have now legalized medical marijuana.

Canada also appears to be headed toward nationwide legalization in the near future.

Importantly, places that have legalized cannabis are doing just fine. Marijuana use among teens in Colorado actually appears to be declining (perhaps now that it’s legal, it’s not “cool”?).

The nightmare scenario of chaos and crime that some predicted simply hasn’t come true.

This trend is only going to accelerate as more states pile on the legalization bandwagon.

Here’s how I summarize the choice faced by many U.S. states today: