You will need approximately 5(5, 7, 7, 7) buttons

Finished measurements:
Back: 9(10 ,11, 12.25, 13.25)“ 23(25.5, 28, 31, 33.5) cm
Length: 8.25(9.75, 11.5, 13, 14.5)” 21(25, 29, 33, 36) cm
Sleeve length: 5(6.75, 7.75, 9, 10.25)“ 13(16, 20, 23, 26) cm

Yarn used:
Rowan Baby Merino Silk DK
Deep 682 - 3(3 ,4, 4, 5) balls