The Ukrainian economy stabilized by the end of the 1990s. A new currency, the hryvnia, was introduced in 1996. After 2000, the country enjoyed steady real economic growth averaging about seven percent annually. A new Constitution of Ukraine was adopted under second President Leonid Kuchma in 1996, which turned Ukraine into a semi-presidential republic and established a stable political system. Kuchma was, however, criticised by opponents for corruption, electoral fraud, discouraging free speech and concentrating too much power in his office. Ukraine also pursued full nuclear disarmament, giving up the third largest nuclear weapons stockpile in the world and dismantling or removing all strategic bombers on its territory in exchange for various assurances (main article: Nuclear weapons and Ukraine).