Was the temple built in 46 years or was it 46 years old during Jesus' time?

I stumbled on this verse again and would like some clarification: > Then said the Jews, Forty and six years was this temple in building, and wilt thou rear it up in three days? John 2:20 (KJV) - Was the temple 46 years old at that time? - Was the temple built in 46 years? If it's the second option, how could it be true that the temple took so long to build? Were they short of labour, money, etc.?