Thanks for sharing David. This is great! Small code error with 'user' and 'usr' though. Here's a quick first-year indexing to flip the takeaway: lang_trend$trend[,3]<-lang_trend$trend[,3]/mean(lang_trend$trend[1:52,3]) lang_trend$trend[,4]<-lang_trend$trend[,4]/mean(lang_trend$trend[1:52,4]) plot(lang_trend)