2.7%, actually (578,759). It lost population in the last 1-2 years.
578,759 is the 2019 vintage estimate (Google's slightly out of date). The 2020 vintage estimate is 582,328. That's splitting hairs, though, anyway. 2020 census results will come out in a matter of weeks.
Probably because despite the oodles of cheap land and tremendous potential for developing a strong renewables market with solar and wind farms, Wyoming has spent the past several decades putting all its eggs in the coal basket. For at least 30 years, Wyoming has been dramatically ramping up coal production at massive surface mines, particularly in the northeast quadrant of the state, to the point that it now dominates the coal market in America. As the coal industry now sings it final swan song, the state finds itself with a needlessly underdeveloped economy. About the only other sectors propping the state up are ranching, which isn't particularly effective at driving population growth, and tourism, which is entirely confined to Yellowstone and Jackson Hole.
Next West Virginia incoming?