Here's a breakdown:
* The 15th edition (1974-1980): 30 volumes
* The 1995 edition (1994-1995): 32 volumes
* The 2010 edition (2009-2010): 29 volumes
* The current online edition: Available on the Britannica website and app, with no specific number of volumes.
It's important to note that these are just examples, and the number of volumes can change depending on the specific edition and format (e.g., print, digital).