In my 60's. According to Internet sources, shorthand was taught in schools until the 1990's. It's likely that shorthand use declined as PCs became common in offices.
I think it was still taught to business students up until the mid-90's in my country. That's also how I got my hands on an old Gregg shorthand textbook. That, and typing (via a typewriter) which was the one I learned when I was in high school.
Had I had a choice, I would have chosen to learn shorthand instead.
I only know about it because of my fountain pen hobby; back in the mid 20th C, Esterbrook made fountain pens with replaceable nibs and offered a wide variety including a Gregg shorthand nib. I guess the Gregg shorthand people licensed the name for marketing. It was basically a normal non, but branded.
Hey! Someone left an old Gregg Shorthand textbook (anniversary edition, if I remember it correctly) in our house back when I was a child, and I tried learning it. Still kinda interested in it up until now.
Tried learning it again back during the lockdown days, but it went nowhere unfortunately.