No one is arguing the number of theist's out there and if numbers proved anything than you might be on to something. The one thing that is certain though is that atheism is the only demographic that is growing and that growth is coming at the expense of Christianity.

>>snip<<

This trend "is big, it's broad and it's everywhere," said Alan Cooperman, Pew's director of religion research.

Christianity still dominates American religious identity (70%), but the survey shows dramatic shifts as more people move out the doors of denominations, shedding spiritual connections along the way.

Atheists and agnostics have nearly doubled their share of the religious marketplace, and overall indifference to religion of any sort is rising as well. Only the historically black Protestant churches have held a steady grip through the years of change.
http://www.usatoday.com/story/news/nation/2015/05/12/christians-drop-nones-soar-in-new-religion-portrait/27159533/

>>end<<

As with conservatism it is made up of older people who, as they die off, are taking their religion with them. Goodbye...

The trend I'm familiar with says Christianity is growing in the U. S. and has been on the.upswing since Obama began openly supporting Islam coincidently with the rise of ISIS, but the information is collected via all church denominations and could reflect reporting bias just as your sources could.

One thing I am sure of is that Christianity is growing at an increased rate world wide. ISIS has caused many to come to Christ in record numbers and interestingly we are seeing Islamics becoming Christian as they are being attacked by terrorists at home.

This information is compiled through reports from Christian missionaries in virtually every country on earth.

In my experience, the reason Christians, including mysekf, repeatedly discuss religion with atheists is because we are taught that to ignore those who do not no know Christ personally, is to abandon them and it is our nature to want all to have what we feel we have. Some Christians go overboard and vilify non Christians and I must admit that I become frustrated when someone tries to deny or box God in based on their personal logic and value system, bht I mean mo distepect until I feel disrespected. At that time my nature to defend comes out and I fire back. I suspect many of us could more thoroughly discuss matters if we were a bit less sensitive.