How empty is the Lisbon to Porto section?

The question was:

I hear often that the section between Lisbon and Porto is really empty of pilgrims going to Santiago, but can you help quantify this for me. If I were to leave on 1st June from Lisbon, how many pilgrims would I be likely to see on the road, and how many would be sharing my albergue at the end of the day? 

Read all about the numbers of pilgrims from Lisbon to Porto here on the forum.