Do you mean: 19.12, 18.13, 16.15, 13.18. 9.22?
The whole number parts are 19, 18, 16, 13, 9 with differences: 1, 2, 3, 4. So the next whole number part would be 9-5=4 so we have: 19, 18, 16, 13, 9, 4.
The fractions parts are 12, 13, 15, 18, 22 with differences 1, 2, 3, 4. The next fraction part would be 22+5=27.
The next number in the sequence would be 4.27.