Although energy drinks were not immune from the effects of the economy, the category has shown its ability to grow in sales. Energy drink sales increased 14 percent to more than $5.9 billion in sales for the 52 weeks ending June 12 in supermarkets, drug stores, gas and convenience stores and mass merchandise outlets, excluding Walmart, according to SymphonyIRI Group, Chicago. The energy shots category also posted strong numbers with a 31.6 percent increase generating $1 billion in sales during the same time period.