Voters in British Columbia have just hours left to get their proportional representation referendum ballots in.

Whether they're mailing them in or still have them in-hand, eligible voters still had time to submit their ballots Friday morning. Not sure what the options are? Here's a quick explainer.

Elections BC estimated about 40 per cent had been returned, or just over 1.3 million. It's a number that has the "no" side – those who want the way B.C. votes to stay the same – a bit worried.

"It really would be a shame if just over 20 per cent of British Columbians decided to change our electoral system when 80 per cent either voted against it or didn't vote," said Bill Tieleman, president of the "no" campaign.

During provincial elections in 2005 and 2009, voters were asked about electoral reform. Both times, they opted not to change the system.

This year's referendum stems from an election promise, and when officially announced sparked months of debate.

"They've launched this question the day before the Legislature is slated to rise for the summer. That is a sleazy and manipulative step they have taken to avoid public debate," Liberal Leader Andrew Wilkinson said back in May.

Earlier this fall, Premier John Horgan said, "We're talking about co-operation that will lead to governments that will work together, where a majority of the votes cast will be reflective of the governments of the community."

Still not sure which side to vote for? Some experts say it's as simple as which political party you support. Here's a look at who wins and loses with each system.

Those who still have them are asked to take them to an Elections BC office. Locations of the offices, which are in most cities across the province, can be found online. 

Officials estimate it will take a couple of weeks to count the ballots.

With files from CTV Vancouver's Allison Hurst