Nothing less than 100% purity is sufficient for our standing before God. James 2:10 tells us clearly that, "whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it." And Paul tells us, "Cursed be everyone who does not abide by all the things written in the book of the Law, and do them" (Galatians 3:10). Jesus himself tells us that our righteousness must exceed that of the Pharisees if we are to enter the kingdom of heaven (Matthew 5:20).
So what are we to do? I don't know anyone who is 100% without sin. I'm not sure I know anyone who is 90% without sin. (Sorry, Dear Reader, not even you!). Well, that's not actually true...the 100% without sin part. I do know someone like that. His name is Jesus of Nazareth. And those who repent of their sins and believe in him are clothed with his righteousness.