Over the past 10 years, several states in the U.S. have legalized medical marijuana, while four—Washington, Oregon, Colorado, and Alaska—have legalized recreational use. Meanwhile, poll data shows that a majority of Americans support outright legalization for the first time. As of January, 23 states and the District of Columbia have laws that allow marijuana use of some kind, and we can expect to see additional ballot measures addressing the issue in the years to come.

The legal changes have been a boon for legitimate businesses, which are scrambling to get a piece of the more than $40 billion U.S. consumers spend per year on the drug, according to an estimate from the Rand Corporation.

These companies must tread lightly since cannabis remains illegal on the federal level and in most countries around the world. At the same time, many analysts believe that the pot industry is ripe for consolidation as more legal barriers come down. After all, the weed market would benefit from economies of scale, and the company that successfully captures the public’s imagination with the right branding could be a nationwide player.

David Sealy, an analyst with The Boston Company, argues that Big Tobacco companies are well positioned to use their experience selling cigarettes and dealing with zealous regulators to create a cannabis oligopoly. But any empire builder worth his salt won’t be satisfied just with the U.S. market. The rest of the world is also rethinking marijuana prohibition, with countries like Uruguay allowing a legal and regulated cannabis industry to form this year.

Here are the biggest pot economies in the world, according to data compiled by the Rand Corporation. Rand ranks these countries not by total size of the market for cannabis, but by the percentage of GDP devoted to cannabis in each country, as this measure gives us a better idea of the depth of popularity of the drug in each country.

You’ll notice the U.S. doesn’t make the cut. While Americans spend more on pot than any other developed country, the U.S. also has the largest economy in the world. When you compare American pot purchases to its massive economy, we only spend 0.14% of our total income on the drug, good for 14th place.

1. Latvia—0.64% of GDP

The fact that cannabis is unlawful to buy, sell, or produce in this former Soviet Republic has not stopped the marijuana trade from bringing in over $97 million of the plant per year, according to Rand Corporation data. In a country of just under 2 million citizens, that's about $48.50 spent on pot per year for every man, woman, and child.

2. Australia—0.47% of GDP

Any way you cut it, Australia's cannabis market is huge. In nominal terms, the Rand Corporation estimates that Aussies spend roughly $3.2 billion per year on pot, even though it is illegal to possess the drug across the country. Penalties for marijuana use vary from state to state, with some jurisdictions issuing fines for those caught with small amounts, while getting caught in others might lead to mandatory treatment.

3. Czech Republic—0.45% of GDP

Like the United States, the Czech Republic has liberalized its attitude toward cannabis in recent years. The eastern European nation legalized marijuana for medical purposes in 2013, and recreational users can carry up to 15 grams of pot without risking a criminal charge.

4. Slovenia—0.36% of GDP

Marijuana possession in Slovenia is a misdemeanor offense punishable by a fine, but enthusiasts in the country are increasingly turning toward non-profit cannabis clubs that only help members get their supply. Though the pot industry in the country has a turnover of about $120 million, that number is pretty significant for a small country of just over 2 million people.

5. New Zealand—0.35% of GDP

Getting caught with pot can put you in prison for three months in New Zealand, but that hasn't quelled the island nation's demand for cannabis. According to polls, nearly half of the country thinks pot should be made legal or decriminalized. And Kiwis are voting with their wallet, too: Rand estimates that the turnover in the marijuana industry is roughly $366 million, or more than a third of a percent of New Zealand's GDP.