Mariah Carey made her recording debut in 1990 under the guidance of Columbia Records executive Tommy Mottola and became the first recording artist to have her first five singles top the U.S. Billboard Hot 100 chart. Following her marriage to Mottola in 1993, a series of hit records established her position as Columbia's highest-selling act. According to Billboard magazine, she was the most successful artist of the 1990s in the United States. Following her separation from Mottola in 1997, Carey introduced elements of hip hop into her work, to much initial success as well. Carey was named the best-selling female pop artist of the millennium at the 2000 World Music Awards. She has the most number-one singles for a solo artist in the United States (eighteen; second artist overall behind The Beatles), where, according to the Recording Industry Association of America, she is the third best-selling female artist and sixteenth overall recording artist. In addition, Carey has earned five Grammy Awards and is well-known for her vocal range, power, melismatic style and use of the whistle register. She is ranked as the best-selling female artist of the U.S. Nielsen Soundscan era (third-best-selling artist overall), with shipments of over 62.5 million albums in the U.S. and has sold more than 200 million albums worldwide. Mariah Carey continues to tour the world.