What Year, How Many Years
noun
You have the kanji what and year, as in: "what year is it?" This also means how many years too, depending on the context. As in: "How many years did you play soccer?"
なんねん
The readings are both the readings you learned with the separate kanji, meaning you should know them. How many years have you been studying kanji now? You should be able to read this one.
ご主人は、何年生まれですか？
What year was your husband born?
何年くらいアメリカにいましたか？
How many years have you been in the United States?
兄にはもう何年も会ってません。
I haven't seen my brother in years.