The pin version of bowling is often played on a flat wooden or other synthetic surface (which can be oiled in different patterns for different techniques), while in target bowling, the surface may be grass, gravel or a synthetic surface. The most common types of pin bowling include ten-pin, nine-pin, candlepin, duckpin and five-pin bowling, while in target bowling, bowls, skittles, kegel, bocce, carpet bowls, pétanque, and boules, both indoor and outdoor varieties are popular. Today the sport of bowling is played by 100 million people in more than 90 countries worldwide (including 70 million in the United States), and continues to grow through entertainment media such as video games for home consoles and handheld devices.