Intransitive verb and Ichidan verb
ふえる
ここ5年間、ビエトの一日当たりの飲酒量が増えてきています。
Over the past five years, Viet’s daily amount of alcohol has been increasing.
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means increase, so the vocabulary verb version means to increase. This is when something is just increasing on its own, and you're not doing the increasing. You know this because you like to err (える) on the side of caution and not touch anything when it's increasing, therefore you're not doing any of the increasing yourself (it's just happening).
It would be foolish (ふ) of you to touch anything while things are increasing anyways. You don't want to mess up a good thing, do you? Don't be a fool.