I was just looking at 12 different missals I have from 1938, 1938, 1939, 1942, 1945, 1948, 1950, 1953, 1953, 1956, 1959, 1959 all use Holy Ghost. I know the Marian Missal of 1962 that the SSPX uses says Holy Ghost, as well as all the missalettes I see in all trad chapels.
I have a 1966 missal and it says Holy Spirit. When did they all change to Holy Spirit?
I finally had a chance to search the King James and Douay-Rheims Bibles available online for the term "Holy Ghost". I note that in the versions I found online, the King James bible refers to the "holy Ghost", the word, holy, is not capitalized; whereas, the Douay-Rheims bibles I found all capitalize, Holy. Given how grammar has changed over the centuries, I'm not sure how significant this is but it appears that the Protestants consider "holy" as a mere adjective while Catholics consider "Holy" as part of His very Name.
The King James bible contains 78 uses of the phrase while the Douay-Rheims bible contains 89 uses.
It is interesting to me that, while the Protestant bible clearly identifies the "holy Ghost", every Protestant I've ever heard refer to the Third Person of the Blessed Trinity has verbally used, "holy Spirit" or, simply, "the Spirit".
As to the question, when did "they all change to Holy Spirit?", I note that an elderly gentleman at my parish tells me that in the early 1960s, when he was in high school, the pastor told his class that, for now on, they would all say, "Holy Spirit" because they didn't want to "scare" children. My friend said that everyone in the class thought that was just plain silly. He said sometime in 1965, the pastor handed out a sheet with the English language responses for the Mass and told them to learn these as this is how they will respond beginning the following month at daily Mass for the school. He told me that none of the kids paid any attention because they thought he was playing a joke, but he was very mad at them when he started saying Mass in English and no one knew the responses.