1.32% is all offensive touches including passes.
He has never had more than 1 fumble in a season on passes.
From AdamJT13
He has never actually fumbled on 182 career rushes or 24 career kickoff returns. The one "fumble" he is credited with on a rushing play was not a fumble -- his knee was clearly down, and the ball went out of bounds. Since there was no turnover and no reason to challenge it, the "fumble" was never reviewed.
Also, he has three actual fumbles on receptions. His fourth "fumble" on a reception was actually an attempted lateral pass on one of those last-second plays when the losing team is throwing the ball around hoping for a miracle. Austin's lateral was recovered by the opponent.
On his 222 fielded punts, he has muffed 13 of them (four of which resulted in a turnover). He has fumbled four times during a punt return, but none of them resulted in a turnover.
So his problem, clearly, has been only muffed punts. Once he has the ball in his hands, he is no more likely to fumble than the majority of other players.