When did we start saying 'was like' instead of 'said'?

I have to admit the saying is kind of insane. Slang is somthing that evolves over time. People were comparing things to one thing and saying like, so then people started just using it to describe what had happened. To be exact, ... well you really can't be. It is just somthing that devolps over time. One person said it occasionally, and then frequently, and then others followed and did it occasionally, and then frequently, and so on and so on until it is just a normal part of speech.