Hi Mille,
It was about 20 000 at the end of the 19th century, many of whom were immigrants. At that time the sponge industry was booming, along with its ancilliaries, and people actually came to Symi from other islands, including Crete, to look for work.
Symi was literally the industrial hub for the surrounding mainland. All those windmills were for grinding wheat grown in other places. Cattle were brought over by caique for slaughter and the leather was tanned down in the harbour, by the Kateraktis. Families had farms across the water in Asia Minor but lived on Symi. If you ever go over to Datca and ask a taxi to take you to so-called Old Datca, you will see Neo-classical houses exactly like the ones on Symi. You may remember, before your SV subscription expired, an article we wrote about Andonis the Andarte, the forebear of one of our Pedi neighbours, who was a sheep 'rustler' over near Bosburun, opposite Pedi.
There are records, but they are in Turkish as the island was still part of the Ottoman Empire. It was really when Symi became an Italian outpost that economic decline kicked in and people started to emigrate en masse.
Concerning donkey poo, we muck out our neighbour's donkey shed as he's getting a bit old to do it himself and he lets us have as much as we want for our land. If it isn't well rotted down, it is a great way to plant grass in the vegetable beds! Just add water and it sprouts overnight.
ops: .. and then spend the rest of the winter pulling it out