Skateboarding has grown significantly in popularity since 2002, with an estimated 13.5 million skaters worldwide according to a sports report. Most skaters are teenagers and men, who use skating as a way to express their individual style. Skateboarding originated from street culture and is often practiced in public spaces not traditionally intended for the sport. Skaters have developed a variety of tricks while sliding on a board with wheels, many of which involve lifting the board and spinning in the air. Famous skaters who have advanced the sport include Tony Hawk, considered one of the most skilled and versatile skateboarders in the world.