Thank you for the information.
My grandmother bought mine from a door-to-door salesperson in 1969, right after my grandfather had died, and she had the house to herself and some money to blow for the first time in her life. The salesperson joked that he didn't even get to use his pitch, because she had already been shopping for one and knew all about them.
It was the only vacuum cleaner in my house the entire time I was growing up, and it totally spoiled me. No other vacuum has ever seemed anywhere close to its quality. I inherited it a few years ago when my dad died. At some point, I guess my grandmother ran over the hose with her car when vacuuming it out. It is smashed and unusable, so I need a new hose to use it. The unit itself seems just as strong as ever, though.