In 1991 issue of American Hiker:
"One trend we couldn't help to notice over the last 2 decades was the decline in the number for overnight campers in the backcountry".
According to NPS, backcountry permits were 1/2 what they were in 1976. Then they go on to say,
"we're only experiencing a temporary lull in the backcountry".
Funny how "temporary lull" is 15 years long and we all know it's gotten so bad since then that now nearly everywhere you go there is some kind of fee to pay to be on the trail, in the backcountry, stay overnight, or simply just be there.