According to the chapter, there are currently about as many people in the world who consider themselves religiously "unaffiliated" as there are Muslims. This means that the number of people who do not identify with any particular religion has increased significantly over the years and is now comparable to the number of Muslims in the world.
The rise of the religiously unaffiliated has been a global trend, but it is particularly evident in Western countries where people are less likely to identify with a particular religious tradition. This is due to factors such as secularization, the decline of organized religion, and the rise of individualism and skepticism towards traditional religious institutions and dogmas.
However, it is worth noting that while the number of unaffiliated people has increased, religion remains an important aspect of many people's lives around the world.