(NewsNation) — Overall support for the death penalty in the U.S. has fallen to 53%, the lowest level in five decades, according to a Gallup study released Thursday. A majority of millennials and Gen-Zers do not support the death penalty, the research found based on aggregated data from Gallup’s annual crime survey, which dates back to 2000. An average of 66% of American adults supported the death penalty from 2000 to 2006, compared to 61% from 2010 to 2016. How Colorado uses a deck of cards to help solve cold cases The last time support hovered around 50% was in 1972, the year the Supreme Court banned the death penalty. The court reinstated the death penalty in 1976, and the following year, a man was executed by firing squad in Utah. Gallup's research suggests people classified as Gen-Z (ages 12 to 27) are more likely to oppose it than millennials. "Younger generations’ exposure to the issue has come when many states had moratoriums on the death penalty or repealed laws that allowed capital punishment," Gallup said. "These efforts were often motivated by cases in which death-row inmates were later found innocent of the crime for which they were convicted." Support levels also differ by political party. "The percentage of Republicans in favor of the death penalty has generally held steady over the past 25 years," Gallup said. "The change in attitudes by generational group is thus seen more among political independents and, especially, Democrats." Since 1976, the most common methods of execution have been lethal injection, electrocution and lethal gas.