please note that the y-axis is scaled, I compared it with the words 'transgender' or 'hacker' and the "intriguing peak" you mention flattened out. Which raises the question of at which point is a change significant in that graph.
Yes, it's not as common as those words. But going from zero use outside of legal documents - as a contrast to "minor children" or less precisely "small children" - to a post-seventies psychobabble and recovery movment term of art is easy to read off that graph.
