Context: In 1991, the KFC name was officially adopted, although it was already widely known by that initialism. Kyle Craig, president of KFC US, admitted the change was an attempt to distance the chain from the unhealthy connotations of "fried". The early 1990s saw a number of successful major products launched throughout the chain, including spicy "Hot Wings" (launched in 1990), popcorn chicken (1992), and internationally, the "Zinger", a spicy chicken fillet burger (1993). By 1994, KFC had 5,149 outlets in the US, and 9,407 overall, with over 100,000 employees. In August 1997, PepsiCo spun off its restaurants division as a public company valued at US$4.5 billion (around US$6.5 billion in 2013). The new company was named Tricon Global Restaurants, and at the time had 30,000 outlets and annual sales of US$10 billion (around US$14 billion in 2013), making it second in the world only to McDonalds. Tricon was renamed Yum! Brands in May 2002.

Question: How many more billion in annual sales did Tricon Global Restaurants have in annual sales in 2013 compared to 1997?

Answer:
4