Downton Abbey ended its official Season 3 run on the UK’s ITV Sunday night with an average 10.1M viewers and a 39.1% share. The score marked a high for the season which had previously peaked in the overnights on October 21. With an overall average of 9.7M viewers, the third season has become the highest-rated for the period drama – Season One averaged 8.4M and Season Two had 9.5M.