 shifting Philips curve in practice. So, why did the original Philips curve relationship apply to many historical cases? The original relationship between inflation and unemployment, the originally negative relationship perceived, it holds up as long as expected inflation and the natural rate of unemployment are approximately constant. So, that relationship holds up to that time, until there are two things that will be constant, expected inflation and natural rate of unemployment. This was true in the United States in 1960s, so the Philips curve appeared to be stable. Why did the US Philips curve disappears after 1970s? In the 1960s, we thought that there are certain things, but why did it break? Both the expected inflation rate and the natural rate of unemployment varied considerably more in the 1970s than they did in the 1960s. Both the expected inflation rate and the natural rate of unemployment also changed. Especially important for the oil prices shocks, because of the oil prices shocks in the 1970s, the expectations of people started to increase, and the expectations of people would also increase. So, there was a lot of variation in the expected inflation. And, why did the natural rate of unemployment change? The composition of the labour force changed in the 1970s. And there were other structural changes in the economy as well, raising the natural rate of unemployment. So, the composition of the labour force means that in the labour force, for example, if a female participation rate is increased, it will have an impact. If a teenager's participation rate is increased, it will have an impact. So, because of these changes, the natural rate of unemployment changes in the 1970s. Monetary policy was expansionary in the 1970s and leading to high and volatile inflation in the 1970s. And plotting unanticipated inflation against cyclical unemployment shows a fairly stable relationship since the 1970s. So, in a module, we saw that after the 1970s, the relationship between inflation and unemployment did not show any pattern. But if you observe unanticipated inflation and cyclical unemployment, then you can see the graph here. What are we taking on this axis? Cyclical unemployment. What did we take first? Simple unemployment. And we are taking this axis which is unanticipated. So, in this, you can see that you can see a negative relationship. So, the relationship between unemployment and inflation is not stable. There is a negative relationship, but it is not stable. Why is it not stable? Because it depends on two things. On expected inflation. And secondly, it depends on the natural rate of unemployment. So, if you account for this, then you can see there is a stable negative relationship. Thank you.