No founder, sponsoring organisation or first observance is documented for National Jose Day. The earliest archived third-party listing of it was captured in August 2022, which dates the listing rather than the day itself.
Three generations of first place
Spain's population register lets you sort names by the decade their bearers were born, and José sits at the top of three of them. Among men born before 1930 it leads at 86.9 per 1,000. It leads again for the 1930s at 86.0, and again for the 1940s at 69.8.
Then Antonio took it. José fell to second in the 1950s cohort, at 48.9 per 1,000. By the 1960s cohort it was third, at 28.7.
Read only that column and the story looks like a simple decline.


