The UNESCO standard is meant for developing countries.

In 2021, California spent about $121 billion on K-12, out of a GDP of $3.4 trillion, or about 3.5% of state GDP. That puts it above the OECD average of 3.3%, around the same as France at 3.5%. blob:https://www.oecd.org/702dcc03-0749-41b6-af41-112fd1af1bfb. (This is the parent page: https://www.oecd.org/en/data/indicators/public-spending-on-e.... You have to select non-tertiary education, which is basically what we call K-12.)