单项选择题

America is a country on the move. In unheard of numbers, people of all ages are exercising their way to better health. According to the latest figures, 59 percent of American adults exercise regularly-up 12 percent from just two years ago and more than double the figure of 25 years ago. Even non-exercisers believe they would be more attractive and confident if they were more active.
It is hard not to get the message. The virtues of physical fitness are shown on magazine covers, postage stamps, and television ads for everything from beauty soaps to travel books. Exercise as a part of daily life did not catch on until the late 1960s when research by military doctors began to show the health benefits of doing regular physical exercises. Growing publicity (宣传) for races held in American cities helped fuel a strong interest in the ancient sport of running. Although running has leveled off in recent years as Americans have discovered equally rewarding and sometimes safer forms of exercise, such as walking and swimming, running remain the most popular forms of exercise.

According to the passage, what was the percentage of American adults doing regular physical exercises two years ago()

A. About 70%.
B. Nearly 60%.
C. Almost 50%.
D. More than 12%.