Boletín Estadístico
Chapter 4: Credit Institutions (data from supervisory returns)
TABLE 4.28: Lending by the aggregate banks, savings banks and credit co-operatives, and of each of the groups of institutions of which it is composed, to general government and other resident sectors. Breakdown by province. Time series
The CSV files that can be downloaded from this page contains the time series relating to the columns on the table 4.28 (eg.: the file be042801.csv contains the series which data on column 1 of the table 4.28 belongs to)
CREDIT INSTITUTIONS
4.28.3. Other resident sectors 
BANKS
4.28.6. Other resident sectors
SAVINGS BANKS
4.28.9. Other resident sectors