sluggish toilet flushing

I have a sluggish 2nd story toilet. That last piece of toilet paper never wants to go down. The tank fills fine, and it seems to take about 10 seconds for the tank to empty but the bowl never empties, there is no "swoosh" and "glug-glug" as the water leaves, in fact, there is no enthusiasm at all. We have snaked the tank, removed it from its seat and cleaned out the pipes underneath, but it still has no enthusiasm while flushing. Any chance there are lime deposits blocking the emptying of the tank into the bowl, and should we probably invest in a new toilet, this one is from 1972?? Advice???