According to The NPD Group, sales for the British toy market increased by 4 percent in revenue during the first three months of the year, primarily fueled by the popularity of collectible toys. The trend saw a 9 percent increase in revenue growth. The building sets and plush categories also fared well. Toy sales up to the first three weeks of March grew 7 percent in value. NPD estimates that the first quarter of 2011 represents approximately 16 percent of annual sales.