Google trends search interest is a commonly misunderstood metric. It measures interest relative to all google searches in a given time period or area.
So if the population of country A is searching 1 billion times a day but only 5 million searches are about bitcoin, then it'll score way lower in search interest than country B, where the population is searching 100 million times a day and 1 million searches are about bitcoin. And yet, the total number of people searching is 5x higher in country A than B.
With that said, the 80 million users number we previously published was a conservative lower bound, before more extensive studies were done. Our upper bound went to 130 million at the time.