Bocatrip

I've noticed my rear suspension area to be creaking when driving. When I push up and down on the trunk the creaking is distinctive every time I push down. The car does not bounce and returns to it's original position after pushing down once. I have not gotten a chance to get it diagnosed. I fear it's the struts, but was wondering if there are any other suspension parts making a similar sound? As long as the rear struts are still functioning normally, I'll live with it for the time being, but was hoping it might be something else. If not... I'll try to wing it until progressive deterioration or failure. My car currently has 159,000 miles and the front struts were replaced about 120,000 miles. Any thoughts out there? Thanks all.