When did “How I Met Your Mother” become less legen.. wait for it… | Data and Analysis with R, for Work and Fun

When did “How I Met Your Mother” become less legen.. wait for it… | Data and Analysis with R, for Work and Fun:

"Enter IMDB average user ratings of every episode of How I Met Your Mother (until season 9, episode 5).  Once I brought up the page showing rated episodes by date, I simply copy and pasted the table into LibreOffice Calc, saved it as a csv, and then loaded it into R.  As you can see in DiffusePrioR’s post (and also in mine), the purpose of the changepoint package is to find changepoints, or abrupt baseline shifts, in your data."

Looking at the structural change in the data. This may be something that can be used in the regime-change paper.  At what point did things change?  What was happening then?