According to wikipedia:
The 1877 census of the Philippines = 5,567,685 people (excluding non-Christians).
The 1887 census of the Philippines = 5,984,727 people (excluding non-Christians).
The 1903 census of the Philippines = 7,635,426 people
(the 1898 census wasn't finished...I assume for obvious reasons).
Demographics of the Philippines - Wikipedia
en.wikipedia.orgCensus in the Philippines - Wikipedia
en.wikipedia.org
The 1877 census of Spain = 16,622,175 people.
The 1887 census of Spain = 17,549,608 people.
Demographics of Spain - Wikipedia
en.wikipedia.org
The 1878 census of Portugal = 4,550,699 people.
The 1890 census of Portugal = 5,049,729 people.
Demographics of Portugal - Wikipedia
en.wikipedia.org
The 1881 population of Iberia would probably be about 21 million. I'd say that the Philippine population would be just over a quarter of that.
Thanks, I was already guessing the population of European colonies would be far less compared to the mainland before 1950.