Evolutionist: why do you say 99.9% of scientist/biologist believe in evolution?

A 2009 poll by Pew Research Center found that "87% of scientists say that humans and other living things have evolved over time and that evolution is the result of natural processes such as natural selection. (WIkipedia quoting the Pew research center) Of course this poll surveyed all scientists not just those whose field dealt specifically with biology. I'm sure that if the all biologists were polled, the number would be very close to 99 percent.