Corruption in Venezuela is considered very high by world standards and is prevalent at all levels of the Venezuelan social scale. In the particular case of Venezuela, the discovery of oil at the beginning of the 20th century has worsened political corruption. While corruption is a difficult variable to measure reliably, Transparency International (TNI) currently positions Venezuela among the 5 most corrupt countries in the world. In the 2014 Gallup poll, it was found that 75% of Venezuelans believe that corruption is widespread throughout the Venezuelan government. Generalized discontent due to corruption was cited by opposition groups as one of the reasons for the marches in Venezuela since 2016.