We have overnight ratings from Showbuzz Daily.
 
  Live Ratings (Overnights) Final Same Day Live +3 Day Live +7 Day
18-49 .3 0.3 0.55(+86%) .64(+115%)
Total Viewers 1.311 1.303 1.95(+50%) 2.16(+66%)
 
This still puts us in second place after The Flash in the demographic and total viewers.
 
For ratings for all episodes check out Supernatural Ratings, All Seasons by Episode.