The introduction of government spending added ____ million(ZAR) to the autonomous total spending in the economy.

The initial aggregate spending equation given is $A = C + I = 40 + 0.5Y$. In this equation, the autonomous component (the intercept when $Y=0$) is 40.

The graph also shows a horizontal line labeled $G = 20$. This represents government spending, which is an autonomous component of aggregate demand.

The question asks how much government spending added to the autonomous total spending. From the graph, the value of government spending ($G$) is 20 million (ZAR).

The introduction of government spending added $\boxed{\text{20}}$ million (ZAR) to the autonomous total spending in the economy.