 Over time, inequality has, on average, been increasing.This is due to numerous factors including labour supply and demand shifts as well as institutional changes in the labour market.On the shifts in labour supply and demand, factors include demand for skilled workers going up more than the supply of skilled workers and relative to unskilled workers as well as technological changes that increase productivity; all of these things cause wages to go up for skilled labour while unskilled worker wages stay the same or decline.