My apologies as the following aren't complete years, but I will work on putting a full year together. For now, here are a few:
November 25, 1978 - "Le Freak" Chic - 37 to 6
April 28, 1979 - "Hot Stuff" Donna Summer - 79 to 29 (just added per seminolefan's post)
June 2, 1979 - "Ring My Bell" Anita Ward - 39 to 19
August 11, 1979 - "Don't Bring Me Down" Electric Light Orchestra - 41 to 18
October 13, 1979 - "Heartache Tonight" Eagles - 52 to 15
October 20, 1979 - "Tusk" Fleetwood Mac - 40 to 15
October 20, 1979 - "Still" Commodores - 38 to 10
November 3, 1979 - "No More Tears" Donna Summer and Barbara Streisand - 33 to 10
August 9, 1980 - "Upside Down" Diana Ross - 49 to 10
May 1, 1982 - "Heat of the Moment" Asia - 55 to 20
June 26, 1982 - "Eye of the Tiger" Survivor - 42 to 19
October 2, 1982 - "Heart Attack" Olivia Newton John - 39 to 13
October 30, 1982 - "Truly" Lionel Richie - 36 to 14
November 20, 1982 - "The Girl Is Mine" Michael Jackson and Paul McCartney - 36 to 14
November 20, 1982 - "Sexual Healing" Marvin Gaye - 52 to 19
After thinking about this--even if a song jumped 20 notches or more and only part if it was in the top 40, if at least 20 notches of that jump
were in the top 40, shouldn't that count? In other words, take "Eye of the Tiger" and "Body Language". Even though "Body Language" had a bigger jump, only 7 of it's 29 notches fell within the top 40. However, "Eye of the Tiger" may have jumped only 23 notches, but 21 of those were in the top 40, which seems like it should count. Pete and dukedeb--any thoughts since you were the originators of this thread?
A few more of significance that jumped more than 20 notches, but only partially within the Top 40:
July 7, 1979 - "Good Times" Chic - 50 to 25
August 1, 1981 - "Who's Crying Now" Journey - 56 to 30
August 29, 1981 - "Start Me Up" Rolling Stones - 61 to 35
May 15, 1982 - "Body Language" Queen - 62 to 33