Not on the app. Maybe late in the interview process when I've got them hooked. But generally not there either. The reason I usually give is:
The work you want me to do is very different than the work I am doing now (or just finished) so any comparison would be meaningless.
Once I applied for a gig with Martin Marietta and the hiring manager thought I was asking for a lot (Hey, quality isn't cheap) but he was willing to pay it if I could show I made within 10% of that number last year. I gave him my reason and he said he still needed confirmation as a policy so I whipped out my paystub, backing up my claim.
So now he's eager to hire me as a senior person and pitching the great work environment - so I told him I wouldn't work for someone who insisted on invading my privacy that way and maybe his company ought to rethink their policies as it was costing them their best candidates. Adios!
Its none of their business. You cost what you cost.