When did the term "catsup" fall out of favor?

When I was a kid in the late '70s and '80s I remember quite a few brands of what seems to be almost universally known as ketchup were called "catsup". I think Hunt's and Del Monte as well as quite a few store brands used "catsup" while Heinz used the term "ketchup" for their brand of that ubiquitous condiment. I'm trying to remember when catsup fell out of favor. Are there any regions around the country or elsewhere where it's still referred to as catsup? 

Just a random thought I had. I was bored at work yesterday and was looking at old issues of Life magazine on Google Books. There were quite a few ads for catsup and ketchup back in the 1960's especially.