In a nation with an opt-out policy, consent for organ donation is presumed upon death, although one can choose not to donate by submitting documentation. Research shows a 25-30% increase in the amount of available organs in opt-out countries.[42] In nations with an opt-in policy, like the United States or France, a person may choose to donate their organs during their lifetime. In opt-in countries, families have on occasion succeeded in overturning the deceased's decision to donate.