For the fifth straight year, total membership in the Southern Baptist Convention (SBC) declined. Membership fell nearly one percentage point to just less than 16 million members. Baptisms and the number of churches rose slightly—by 0.70 percent and 0.08 percent, respectively. Baptisms hit a 60-year low for the denomination, though still totaled more than 330,000. The denomination planted almost 1,000 new churches, of which 50 percent were non-Anglo; however, the net gain of 37 churches was one of the lowest totals in 40 years.
These trends are not new but should refute the claim that mainline decline is due to liberal theology and progressive social stances. Read the article here.
Preaching Grace on the Square 
“…but should refute the claim that mainline decline is due to liberal theology and progressive social stances. ”
Except… it doesn’t. Southern Baptists are leaving for independent Baptist churches and independent Evangelical churches precisely because of the changing politics of the SBC. As the SBC began to sound like a mainline group, their numbers started to drop. The SBC is still theologically conservative compared to mainline groups, but their change in direction has been undeniable.
I’m not going to debate the reasons for numerical decline in the SBC with you, but I can’t imagine any legitimate argument that would cite its liberal tilt. In fact, its decline corresponds with its takeover by the fundamentalist wing.