Please Help Explain 1:33 Solera

Emilio Lustau: East India Solera

According to sherrynotes.com (https://www.sherrynotes.com/2015/reviews/cream-sherry/east-india-solera-lustau/), Lustau's East India Solera is described as 1:33. Does this imply that there are 33 Criaderas or that 1/33rd of wine is removed/moved as Saca per year?

Any clarification would be great! Thanks for your help.