<human>:  How have music sales changed over time?
<bot>: Music sales have been generally declining over the past decade due to the rise of digital music streaming services. With the advent of these platforms, people can access a larger selection of music without having to purchase it. This shift has caused a decrease in physical music sales, but an increase in digital downloads as well as streaming revenues. Additionally, subscription-based streaming services have also grown in popularity, helping to offset some of the losses in physical music sales.