According to the Center for Contemporary History, 140 people died at the Berlin Wall or under circumstances directly connected with East Germany's border regime. The figure is commonly used in summaries of people who died attempting to cross the Wall.
The Berlin Wall was built in 1961 to stop East Germans from leaving for West Berlin and West Germany. Escape attempts involved tunnels, forged documents, vehicles, balloons, swimming, jumping from buildings, and attempts to climb or cross the heavily fortified border. East German guards were instructed to prevent escapes, and some people were shot while trying to reach the West.
The number can be confusing because different institutions use different counting methods. The Center for Contemporary History and the Berlin Wall Memorial identified 140 deaths in the broader category connected to the Wall and the GDR border system; another research count has identified 136 people who died directly at the Wall. The total also includes some border guards and uninvolved people, so 140 is best understood as the established research figure, not a claim that every victim was an escapee.