Kind of need a way to measure peasant level income to total wealth available over time. Over the past several hundred years the 'pie' that is total economic go

Kind of need a way to measure peasant level income to total wealth available over time. Over the past several hundred years the 'pie' that is total economic goods and services has grown enormously. However, the share a median income can buy of the pie has shrunk greatly. Inflation vs median income intuitively gives a sense of this while not necessarily being scientific. But then economics is the dismal science.