Answer:
0-19: Make it 4 units tall
20-39: Make it 2 units tall
40-59: Make it 5 units tall
60-79: Make it 3 units tall
80-99: Make it 1 unit tall
Explanation:
0-19: 4, 6, 19, 19 (4 numbers)
20-39: 29, 38 (2 numbers)
40-59: 40, 41, 41, 57, 58 (5 numbers)
60-79: 62, 66, 73 (3 numbers)
80-99: 87 (1 number)