Anonymous Dear reader, That depends on the volcano and the 100 year interval you are interested in.
Some volcanoes can go hundreds, thousands, or even hundreds of thousands of years between eruptions.
So, it depends which 100 years you pick on whether or not there will be an eruption. Some volcanoes can erupt almost continuously for more than 100 years, like Kilauea from 1823-1924. Some volcanoes might erupt many times in 100 years. For example, Mauna Loa in Hawaii has erupted 16 times in the last 100 years. Other volcanoes, like Lassen in California, have only erupted once in the last 100 years.