Hi,
Do you water them? If you don't water them and you are in a zone with dry summer ... You may wait your life long.
You need to supply water to your trees for them to be healthy and hang on to their crop - at least one watering can (11 Liters/3gallons) per tree once or twice a week or even more if the weather is dry for a long period and your tree is loaded with leaves and figs.
A little less water and the fruit size will decrease; a little less, the fruits drop, and even less, the leaves will start to yellow and fall.