What recline angle should the seat be set to for rear-facing use?

For rear-facing installation, lift up on the Recline Adjuster and tilt the seat so the Recline Ball is in the correct zone: the White Zone for children weighing 1.8–9 kg (4–20 lbs) and the Black Zone for children weighing 9–22.6 kg (20–50 lbs). The ball must be completely within the appropriate zone and the vehicle must be on level ground. Failure to properly recline the car seat could increase the child's risk of death or serious injury, as infants may have difficulty breathing in an upright position. (Pages 11, 62)