LAS VEGAS — Former Colorado governor and 2020 long shot Democratic presidential hopeful John Hickenlooper struggled to explain what "GDP" stands for when answering a question during a Service Employees International Union conference in Las Vegas.

"Let's take healthcare as a whole where next year we'll be at 18% of our GDP. Our gross, whatever that stands for, demographic product," Hickenlooper said at a convention center full of labor organizers, union members, and activists in Las Vegas, Nevada." You know, I should know that, I can't even remember."

GDP is shorthand for "gross domestic product," an economic term that measures the total worth of an area's goods and services. The current GDP of the United States is estimated at roughly $19.4 trillion.

Hickenlooper's response was met by an awkward silence and a few groans from the audience and members of the media. Through his speaking time, he complained about his fatigue from being on the campaign trail and struggled through coughs while giving his pitch for why organized labor should support his bid for president in 2020.

"Sure, multiple questions, [the moderator] is counting on the fact that I've been on the campaign trail for a while and I have a short attention span and I'll miss one of those," Hickenlooper said earlier in the event when asked a multi-part question asking him to specify exactly how he plans on bringing down healthcare costs in the United States.

Hickenlooper announced his candidacy on March 4. Polls of primary voters estimate his support among the Democratic electorate at zero to 2%.