1 in 5 Americans now has access to fully legal marijuana

2016 was a huge year for legal marijuana.

Four states - California, Massachusetts, Nevada, and Maine - all fully legalized marijuana use, cultivation, distribution, and sales in the November 8 election. That brings the total number of US states with fully legal cannabis up to eight (plus Washington D.C.).

Skye Gould/Business Insider

Though that's still a fraction of the US, California has an outsized impact - it's the most populous state in the union, with nearly 40 million residents. As a result, 21% of US citizens now live somewhere with access to fully legal marijuana.

More starkly: One in five people in the US now lives somewhere with legal weed.

Eight states (and D.C.) have fully legalized marijuana: Colorado, Washington, Oregon, Alaska, California, Massachusetts, Maine, and Nevada. Between those eight states and D.C., that's just over 68 million Americans.

REUTERS/Steve Dipaola

Marijuana-based products are displayed at the "Oregon's Finest" medical marijuana dispensary in Portland, Oregon April 8, 2014.

By far, the most impactful state to have full legalization is California. With Proposition 64 - the ballot initiative to legalize marijuana - voters overwhelmingly chose yes on November 8.

56% of voters said yes to the initiative.

As of 12:01 a.m. on November 9, marijuana use is fully legal in California. There's a $100 fine for smoking in public, and driving under the influence of marijuana remains illegal. California residents are allowed to grow up to six plants in their homes, and recreational sales from shops will become legal on January 1, 2018. The legislation is similar in the other three states that voted in favor of legalization last week.

The immediate implications for California's economy are huge.

New Frontier Data / Arcview Market Research

California's looking at $1.5 billion flooding into the marijuana market. That number swells to just shy of $3 billion in 2019, and nearly $4 billion by 2020, based on the latest report from New Frontier Data and ArcView Market Research.

The US' most populous state is already pulling in billions annually from medical marijuana, which was legalized in California by Proposition 215 back in 1996. The total size of the cannabis market would reach $4.27 billion in 2018, and would grow to $6.45 billion by 2020 (according to ArcView's projections).

Another question altogether is what impact will the presidential election have on the ongoing push toward nationwide marijuana legalization. The long and short: no one knows for sure, but Bloomberg has an interesting look into how the legal marijuana industry is reacting.