Although Coca-Cola Co. spent nearly $ 2 billion last year advertising its various brands around the globe, it saw its share of the critical U. S. cola market decline. Meanwhile, Pepsi Co. is riding a sizzling Britney Spears-led ad campaign to a bigger share, and has launched an audacious assault on Coke's long-held sponsorships. The cola fight-is heating up, and Pepsi is landing most of the punches. Pepsi's share of the U. S. carbonated soft-drink market rose to 31.65% last year, Beverage Digest reports. Coke brands, including Diet Coke and Sprite, still lead easily with a 43.7%share -- but that's down four-tenths of a point. Both companies' flagship colas, which together account for 1 of 3 sodas sold in the U. S. , lost share last year. But Coke's lost more, and Pepsi scored big with new flavors Code Red and Lemon Twist. Pepsi Co. recently emharrassed its bigger rival by snatching away the National Football League sponsorship, which had been Coke's for 22 years. Coke dismisses the NFL setback as less important than the individual sponsorships it retains with two-thirds of the league's teams. 'We're still an NFL sponsor,' asserts Jeff Dunn, head of Coke in the Americas. He insists that the 'passion point' for consumers is local teams. He says the cost of the league sponsorship had escalated beyond its value. Beneath Coke's outward calm, executives are angry over the NFL loss. Now, some on Coke's board are said to be upset that Pepsi outdid Coke's management. This sets up a marketing brawl later this year as Coke tries to tie itself to NFL from the bottom up, team by team, and Pepsi tries to do the same thing from the top down, leveraging its deal with the league. Coke has hardly been sitting on its thumbs. Last year it brought out Diet Coke with lemon, and the company is now gearing up to launch Vanilla Coke. Yet if Wall Street is the judge of who's winning, there's no contest. Pepsi shares are trading near the all-time high and have almost doubled during Coke's long depression. Pepsi rates a strong buy from twice as many analysts. The news is not better for Coke among advertising experts. 'There's nothing great going on ever there,' says marketing consultant A1 Ries in Atlanta. He gives Pepsi far better marks for 'effectively using visuals like Britney Spears to reinforce Pepsi's image that it is for the young generation,' and for companies that sell very similar sugar water, image is everything. The passage is mainly about ______.