How many times does Google release the algorithms and updates visible to users?

Hi Friends,
How many times does Google release the algorithms and updates visible to users?

Nobody has the time-table :p

12 March 2019 Core Update. Exactly one year after confirming the first of its official "core updates" Google released yet another broad change to its algorithm. Initially picked up by Rank Ranger's Rank Risk Index on March 12th, the update was not confirmed by Google until the 13th.

It looks like Google has rolled out its first significant algorithm update for 2019. Google has not yet confirmed if the algorithm update rolled out during the second week of January is a core or a broad core update. However, the update seems to have made drastic changes to the results shown in featured snippets.

Generally speaking, the company rolls out 500 to 600 changes to its search algorithms each year. However, many of these changes are minor and the average web user wouldn't even notice that changes have taken place. When it comes to major updates and algorithm changes, Google is more conservative with its changes.