20% is the normal range when jumping ship, but if your current pay is very low can ask for more.

Must be careful of recruiters because sometimes they will try and undercut you by telling you industry norm is 10% - 15% because they are very scared that the deal falls through they can't get commission.

I got this recruiter before who I ask for 25% because the new company benefit a little lower try to bullsh!t me to accepting just 15%. I kept insisting no 25% no join and in the end got the offer.

After I join I check with my boss and realise the recuiter actually didn't even communicate my 25% request and instead put in 15% because the 25% exceed the company budget slightly and she was scared the company will reject outright, so she was trying to play both sides by lowering my expectation and force fit into what she thinks the client is prepared to pay.