I'm wondering if anyone has access to census returns from Spain for the Cantabria region. I'm looking for the late 1800's to 1900 or 1901. What years were the censuses in Spain?

I'm searching for:

Dorothea Portez, born 1860-1870, probably in Santander.

William Tregarth Jones, born July 14, 1891, Santander.

Dorothy Jones, born 1886, Wales.

Possibly William Robert Jones, born Bangor, Wales, 1865.Merchant mariner.

The first three were in Spain in 1891.

Regards,
Teresa