Ice Forming in Back of Refrigerator?

I have a 2 door fridge/freezer, not the side by side ones, the half and half type. The freezer works perfectly but I have a problem with the refrigerator section. I defrost and clean it regularly but a week or so after defrosting, a very thick layer of ice forms at the back of the fridge. After a month or so, the ice is about 1 inch thick! It still works fine and everything is cold as it should be but I'm sure this thick layer of solid ice isn't normal.

What is worse, if anything happens to be at the back like a jar or similar, the ice actually grows around it and the container is embedded in the ice. If I delay defrosting for more than two months or so, the layer of ice is so bad that the jar that embedded itself in the ice, completely disappears into the ice. It is not on the coldest setting, just normal for the time of year. It is not opened excessively, just normal for getting things in or out. Does anybody have suggestions? I'm getting tired of having to hammer the ice off the back of the refrigerator every couple of months!

By cettina from Malta, Europe