Wearing a seat-belt reduces the risk of a fatality among drivers and front-seat occupants by 45% to 50%, and the risk of minor and serious injuries by 20% and 45%, respectively.
Download: https://www.grsproadsafety.org/wp-content/uploads/GRSP-Seat-Belts-Fact-Sheet.pdf
Source: GRSP Seat-Belts Fact Sheet