According to the book I'm reading (*), the pay of CEOs tends to increase because the divorce between ownership and control allows for abusive compensation practices by the CEOs. Indeed, in the graph below we can see a near exponential rise in CEO compensation (measured as the ratio between the wage of the CEO and that of the average worker) since the 70s. I've found many sources discussing this topic, but none on the decreasing spikes in the years 1994-95 and the early 2000s. Why did this happen?
(*) Economics by Paul Samuelson, William Nordhaus, 19th Edition. Chapter 6, Figure 6-7.