 Complete the following phrase:  The competition format has changed several times. From the beginning in 1966, the World Championships consisted of only two competitions: an individual race and a relay. In 1991, a short distance race roughly 2025 minutes was added and a sprint race was added in 2001. The middle distance roughly 3035 minutes replaced the short distance in 2003. On IOFs 23rd congress in Lausanne in 2012, it was decided that a sprint relay event would be added in the 