HELENA — It’s hard to keep track of what’s happening with the state and federal government’s efforts to regulate or control medical marijuana in the state.

Here’s a timeline:

November 2004: Montana voters, by 62 percent to 38 percent, approve legalizing the use of marijuana for certain medicinal reasons.

Dec. 31, 2006: A total of 387 people have medical marijuana cards in Montana, with 116 providers registered.

June 30, 2008: The number of people with Montana medical marijuana cards tops 1,000 for the first time, reaching 1,006.

Dec. 31, 2009: Montana has 7,339 medical marijuana cardholders and 1,942 providers.

Dec. 31, 2010: The numbers keep soaring. Montana has 27,292 medical marijuana registered cardholders and 4,807 providers.

Jan. 1, 2011: House Speaker Mike Milburn, R-Cascade, introduces House Bill 161, which would repeal the medical marijuana law that Montanans adopted by initiative.

March 14, 2011: Shortly after the Senate Judiciary Committee deadlocks over HB161, federal agents raid more than two dozen medical marijuana growing and dispensing operations around the state.

March 23, 2011: Senate Majority Leader Jeff Essmann, R-Billings, introduces Senate Bill 423, to greatly restrict the access to and the availability of medical marijuana in Montana.

April 13, 2011: Gov. Brian Schweitzer vetoes HB161, the repeal bill.

May 3, 2011: SB423 becomes law, without governor’s signature.

May 13, 2011: Montana Cannabis Industry Association and others file a lawsuit challenging SB423 and ask it to be enjoined.

June 30, 2011: After a hearing, District Judge James Reynolds of Helena temporarily blocks parts of SB423 from taking effect, but the rest of the law remains in place.

Sept. 29, 2011: Opponents of new medical marijuana law gather enough signatures to qualify SB423 as a referendum, allowing voters in 2012 to decide whether they want to keep or reject the law. The final tally shows they obtained 36,374 of needed 24,337 total signatures needed and qualified it in 72 of the required 34 legislative districts needed.

April 30, 2012: Number of Montana medical marijuana drops to 10,640, the lowest numbers in two years, and 414 providers.

May 30, 2012: The Montana Supreme Court will hear cross-appeals by both the Montana Cannabis Industry Association and state of Montana.

November 2012: Montana voters will decide on a referendum whether to keep or reject SB423.

If backers obtain enough signatures to put Constitutional Initiative 110 on the ballot, voters will decide whether to legalize the right of adults to possess marijuana, subject to reasonable limitations.