I am kind of confused about the meaning of the noun "numbers" in this piece:
Some anxiety that had built around the protests ahead of Wednesday, a holiday to celebrate the founding of the People’s Republic of China, eased as the day wore on and protests in many parts of Hong Kong took on a festive tone, with some demonstrators offering free haircuts and massages. As on other days, numbers shrank in the midday heat and swelled again as evening approached.
I've already checked dictionaries, but I cannot quite pinpoint the correct definition of "numbers" to use.