Grace.....As your question is worded, it can be answered in several ways, I believe. For instance....."more accepted in the Untied States?" With regard to the word "accepted," are you focusing on atheism (disbelief in God/Supreme Being) & agnosticism ( the existence of a God/Supreme Being is unknowable)
OR....are you focusing upon the self-admitted individuals & widespread increase of them? OR, both the concepts & the individuals, in general?
It's fair to say neither will ever be "accepted" by believers-Christians-followers of a God/Supreme Being. People of Faith simply cannot and will not even consider such doubt and denial. I'm convinced this is FACT more than an opinion I'm sharing. Ask any believer anywhere, at any time. They'll be more than happy to confirm and reconfirm this.
However, it's also a fact that the numbers of atheists and agnostics are growing at a steady pace and spreading throughout the U.S.if not the world as a whole (but I have not researched for worldwide). It also seems a new attitude that such people are self-disclosing without hesitation, which has not always been the case. If I can use the comparison here, this tendency to speak up and out in terms of one's atheism/agnosticism has taken the same turn as LGBT's in "coming-out." They've become more comfortable and outspoken, based on pride & dignity being rights of every human being.
The overall apprehensions & fears have subsided, where once this kept people from approaching the very subject.
I did some actual in-depth research on this topic less than a year ago and while I cannot recall the numerous sites, statistics, articles & authors I perused, I recall being quite surprised at most of the information. I can only believe it is pretty much the same a year later, if not that
atheism.agnosticism has gained even more momentum, given the strong & constant influence of extreme left Liberal College Professors, God & Religion continually being "left out" of the public, schools, homes and every day life in America.
So, Grace, if you and I are on the same page with the term, "accepted," I'll have to admit that it's pretty clear that it is precisely that: "more accepted."
At the same time, I'll repeat that this will probably never be "appreciated" by the millions of believers. Good question but difficult to answer. Paula
(Suffice it to say that certainly they have been "accepted" within their own group and like-circles of a community.)