lweji not trying to derail but I'm not sure I understand this bit
it's probably cherry picking as the greatest number they could find
Do you mean that the studies themselves tried to have more impact-worthy findings so presented the data in a way that was most dramatic and that it happened to be that in all the studies that figure was 34%?
Sorry, I feel like this is something I should be able to get and owe to my former tutor but I'm just not at the moment!