The pattern system, overseen by the European Pattern Committee, is fluid and the Group status of key races can change. By this method, the Prince of Wales Stakes at Royal Ascot was upgraded from Group 2 to Group 1 in the year 2000. However, a number of checks and balances are in place which ensure that changes to the Pattern are gradual and evolutionary, thereby giving the racing industry time to adjust. In particular, the current European Pattern Committee "Ground Rules" explicitly state that no race may be upgraded by more than one Group in any one year. Such restrictions can prove troublesome when major new races are launched. For example, the Dubai World Cup, the world's richest horse race, was only given Listed status for its inaugural running in 1996.