Cuba's labour regulations ultimately caused economic stagnation. Hugh Thomas asserts that "militant unions succeeded in maintaining the position of unionized workers and, consequently, made it difficult for capital to improve efficiency." Between 1933 and 1958, Cuba increased economic regulation enormously. The regulation led to declining investment. The World Bank also complained that the Batista administration raised the tax burden without assessing its impact. Unemployment was high; many university graduates could not find jobs. After its earlier meteoric rise, the Cuban gross domestic product grew at only 1% annually on average between 1950 and 1958.