Thanks to everyone who replied to this question. I hope you see my reply although most of you, having already completed your tax forms, have gone away and think...

No help. That iw what the Google search says and if that meant anything to me, I wouldn't be still askiing.

I am NOT self employed so I don't even know how I got here and why I have to fill in line 18. If I have to, shouldI I put in a high number or a low one.