The Suffix -age

Electric potential is also called "voltage" as in the number of volts. Electric current is sometimes called the "amperage". Power, especially electric power, is sometimes called the "wattage". Area when measured in acres is sometimes called "acreage". Have I ever seen "poundage" as in weight in pounds?

So what is "garbage"? There's also "suffrage," by the way. "Universal Suffrage".