These were 2010 figures. That makes no difference. The US population was not 79.5%Christian in 2009, 2010, 2012, or 2013.
A true Christian, then, is one who has had the blood of Jesus Christ’s sacrificial death applied to him or to her—but only after having acknowledged and repented of their sins (toward God the Father) and accepted Christ as their personal Savior (Acts 3:19; 2:38; Ezek. 18:21-23). Repentance literally means a change of mind and attitude, as well as a complete change of conduct. In repentance, one literally turns from the way of sin (breaking God’s law) that leads to death (Prov. 14:12; 16:25; Matt. 7:13) and begins walking God’s way—the true, Christian way of life (John 14:4-6; Acts 16:17; 18:25-26; I John 2:3-6).
The percentage of Americans who actually fit the Biblical definition of what a follower of Jesus Christ is much lower than what this survey claims.
If nearly 80% of the people in the country were true followers of Christ, we would not be in the hellish condition we find ourselves. Sexual immorality, greed, violence, crime, deceit, and self-worship are the prime characteristics of Americans today.