Hi. The percentage of losing in gambling depends on the particular game and its rules. In most cases, the probability of losing is higher than the probability of winning. For example, in slot machines, the probability of winning is often less than 10%, while in card games such as poker or blackjack, the probability depends on the player's skills and strategy.
Casinos and other gambling establishments usually have a mathematical advantage over players. This means that in the long run, most players will lose more money than they win. This ensures that casinos and other gambling operators are profitable.
Here
https://www.choicenotchance.org.nz/understand-gambling/real-life-stories/gabriels-story you can read stories of real players, and see how often people lose at gambling.