I passed my 20 word-per-minute code test a year to the day I passed my Novice exam. Of course, that was back between 1992 and 1993. Just takes a lot of practice. 5 words-per-minute is relatively easy if you study at even 7.5 or 10 words-per-minute. After that, you don't need to test for code, because the 13 and 20 word-per-minute requirements were dropped a few years ago.
These days I probably listen to code on the air more than I use it (18 to 20 words-per-minute is pretty relaxing), but when I do get on the air, my rate is upwards around 35 to 40 words-per-minute.