You’ve read all of your free items this month. To register, get added benefits and unlimited access to articles, Become a Member. Already a Member? Sign in. Advertising Age Article Abstract Decline in Soft Drink Sales Accelerates Despite Big Marketing Investments Coca-Cola, PepsiCo Continue to Spend in Still-Massive Category By Natalie Zmuda, Published on March 31, 2014 5 Want more Access, Content & Connections? Upgrade to Membership. We are glad you are enjoying Advertising Age. To get uninterrupted access and additional benefits, become a member today. Become a Member Already a member? Log in.