According to this (old) paper there are 10 times more mutations during meiosis than during mitosis. One reason for that is that recombination often causes replication error and therefore mutations. However, in many multicellular organisms, germ cells undergo many cell divisions (mitosis during development) before finally undergoing meiosis.
I think that intuitively many people (me at least) think of new mutations* that are transmitted to the offspring as mutations occurring during meiosis. I would like to have a notion of how important are the two processes (mitosis and meiosis) in generating heritable new germ-line mutations in multicellular animals.
Let's consider humans for example. Out of 100 new germ-line mutations transmitted to the babies, how many of those mutations occurred during mitosis (during the development)?
*I call "new mutations", any mutation that is transmitted to a baby but that was not present in any of the two eggs of the parents (even before the parents started the gastrulation).