Christianity the largest religion? Maybe in Word, but Not Deed

According to CNN, the information gathered

"It does not measure practice or belief, merely counting as Christian anyone who says they are."

So what does Jesus have to say to that?

Jesus replied, “You hypocrites! Isaiah was right when he prophesied about you, for he wrote,‘These people honor me with their lips, but their hearts are far from me.

Mark 7:6