According to the news item the volcano had been dormant for about ______.

Itar-Tass news agency said a volcano in Russia’s far eastern peninsula of Kamchatka erupted spectacularly on Thursday for the first time in nearly three decades. Shevelach Volcano, which had been dormant since 1964, spewed clouds of ash high into the air and reverberated with deafening explosion. Residents of Klyuch, 45 kilometers from the volcano, were in no danger but ash could fall on the settlement ff the wind changed. Kamchatka, with most 29 active and more than 200 extinct volcanoes, is one of the world’s most active volcanic zones and forms part of a "ring of fire" surrounding the Pacific Ocean.