How many retail banks, insurances and government departments have still got a mainframe sitting at the very back though, based on a good few engagements in bank

How many retail banks, insurances and government departments have still got a mainframe sitting at the very back though, based on a good few engagements in banks and gov in the UK, I haven’t yet come across where ultimately some mainframe batch job is hidden behind a fair few layers of middleware and MQ. And my guess is that most of that is on COBOL.