It depends on a lot of factors. There is no one answer. The length of your history, your ratio, and a lot of other factors come into play. If you have a lot of accounts, long history, low ratios, it probably won't lose much. If you have fewer accounts with shorter history, the drop will probably be larger.
Hedwig's answer is the fully correct one. Though the general impact is about a 20-30 point IMMEDIATE drop. A 30 day late lessens in effect quicker then "serious derogs", and usually has little effect after a year.
