Statistics on whether users save and come back and finish an account opening application?

I'm redesigning some account openings for financial products that have fed regulations requiring many many fields and am skeptical users take the time to decide they can't finish then click 'save for later' and setup yet another password and email verification to pick up where they left off. We don't have budget to do research - anyone have usage data that shows users successful recover saved account applications forms? Seems to me most reasons for not being able to finish imply you also don't have the time to find save and setup a recovery password...

I'm hoping to find secure way to save in the background and allow a 'resume application link' that allows them to enter enough info to safely pull up their application but I'm worried about criminals trying to hack the same...