PHILADELPHIA--(BUSINESS WIRE)--The top 20 TV series on Xfinity On Demand for the week of February 23 – March 1 were: 1.   Empire, FOX2.   The Walking Dead, AMC3.   Downton Abbey, PBS4.   How to Get Away with Murder, ABC5.   The Last Man on Earth (series premiere), FOX6.   The Blacklist, NBC7.   Better Call Saul, AMC8.   Secrets and Lies (series premiere), ABC9.   The Big Bang Theory, CBS10. The Voice (season premiere, Monday), NBC11. Battle Creek (series premiere), CBS12. Vikings, History13. Th