Between 1982 and 2005 belief in Special creation amongst the American population hovered between 44-47%
2005 was the year of the Kitzmiller trial - a peak year in the evolution vs creationism debate. The year I joined EvCForum!
Between 2005-2011 acceptance in Special Creation dropped from 46% down to 40%, enjoying a brief resurgence in 2012 back to 46% before beginning a five year crash. As of 2017 that number was at 38% - for the first time equalling the number of people that believe in a Theistic Evolutionary perspective.
Since the year 2000 acceptance in evolution alone has gone from 9% to 19%
Since 2000 YEC has dropped in support 0.5 percentage points per year on average, and Evolution alone has increased in its support at the same rate. Education is a big factor in determining acceptance of evolution, theistic or non-theistic. Graduating from college seems to halve the number of people who subscribe to YEC beliefs. Nearly 60% of people accept evolution to some extent now.
It seems evolution is winning the debate against Special Creation, with Theistic Evolution largely unchanged over time. Big court cases (Kitzmiller,2005), flashy productions whining about persecution (Expelled: No Intelligence Allowed, 2008), attempting to change things at a legislative level (Anti-Science bill in Indiana....., 2012) - are either backfiring or merely delaying the decline in YEC belief.
Alongside this trend, an absence of belief in God is rising - especially amongst the young. How long can this debate hold out? Will YEC acceptance continue to crash? Between 2012 and 2017 it dropped 8 points (1.6 points per year). Will we see acceptance of YEC beliefs drop beneath 25% within the decade? Will the rate increase or level out before then?
As the number of believers decrease, the amount of money to be made from them decreases. I believe therefore the decline is practically inevitable, though it may rally a few times before it becomes irrelevant.