A working class is any class in a given class society which produces surplus labor for the other idle, exploiting classes. One or many working classes may exist in a given social formation at a time. The two most common types of working class by far have been the slave class and the serf or peasant class, but in modern capitalist society, the term almost always refers to the proletariat. In modern usage it may also include the millions of smallholding farmers globally who directly sell their produce. However, as Marx predicted, this class has dropped in numbers and influence over the course of globalization and continues to struggle against agricultural capitalism.