Query: During the middle and early parts of what decade did the similarity of Easy Listening and Hot 100 increase?
Context: The Hot 100 and Easy Listening charts became more similar again toward the end of the 1960s and into the early and mid-1970s, when the texture of much of the music played on Top 40 radio once more began to soften. The adult contemporary format began evolving into the sound that later defined it, with rock-oriented acts as Chicago, The Eagles, and Elton John becoming associated with the format.