>I'd guess about half of that identify as Christian because it's socially unacceptable to be agnostic.

That's much less an issue now than 50 years ago though, which is what's important when talking about a relative decline. It was much less socially acceptable to identify as agnostic in 1960 than it is today.

Still a huge issue in much of the US.

On this topic how many days a week do pastors work?

My dad was a music director and assistant pastor. He worked about 5 days a week, and also had another job on the side. Choir practice, church functions and services, preparing sermons, visiting sick church members, counseling members, and doing charity work add up to a good bit of time.

The pastors I'm familiar with all work a typical work week - 40 hours or more. Plus visiting the hospital, counseling, weddings, funerals etc.