Divide 1 to 39 into 20 scales

Divide the numbers from 1-39 into 20 scales, with each scale representing the following numerical intervals:

Size 1st: 1 - 2

Size 2nd: 3 - 4

Size 3rd: 5 - 6

Size 4th: 7 - 8

Size 5th: 9 - 10

Size 6th: 11 - 12

Size 7th: 13 - 14

Size 8th: 15 - 16

Size 9th: 17 - 18

Size 10th: 19 - 20

Size 11th: 21 - 22

Size 12th: 23 - 24

Size 13th: 25 - 26

Size 14th: 27 - 28

Size 15th: 29 - 30

Size 16th: 31 - 32

Size 17th: 33 - 34

Size 18th: 35 - 36

Size 19th: 37 - 38

Size 20th: 39 - 39