Juggernaut! What is it and how old are you?

I used the word juggernaut today when talking to my 17 year old daughter. She didn't know what I meant. My 20 year old equally didn't know of it. Thirty somethings know the meaning, so what is the moment that this word lost its place as a common word in UK English? Juggernaut is a Hindu god but it was a commonly used as a term for an articulated lorry in the 80s. When did it die out? UK English speakers only please, as I guess most Americans, Aussies, Canadians etc wouldn't have ever used it at all.