-1 week S, B, C, O, D 0 week C 6 week R, C 3 months R+, B, C 6 months R, B, C 9 months R+, B, C 12 months R++, B, C, O, D 15 months R+, B, C 18 months R, B, C 21 months R, B, C 24 months R++, B, C, O, D