A similar stylistic fragmentation to that which occurred in classical singing can also be found in pop singing in the second half of the century. In chapter 6 I proposed that jazz singing, the dominant popular style from the late twenties onwards, reached a stylistic plateau with the singing of Frank Sinatra. In fact, by the end of the forties popular singing style as represented by the successors of Armstrong and Crosby was showing the typical signs of decadence that precede a significant change in popular taste. Crosby himself was at the peak of his powers and had many imitators, whose often well-crafted Tin Pan Alley ballads monopolised the record industry's sales charts. The introduction of weekly published charts of bestselling singles began in the USA in 1940, and although the charts were not immune to interference they do provide a better guide to popular musical taste than any indicator previously available. Under segregation the separate markets for ‘black’ and ‘white’ audiences could be easily identified and targeted by the record industry. The first Billboard Best Selling Singles chart was, in effect, a measurement of sales to white buyers. Sales to the black audience were soon sufficiently large for the addition of a separate chart. In 1949 this became the Rhythm and Blues chart, and a Country and Western chart was added at the same time.