my prediction on the dollar exchange rate

I am always surprised that people are shocked.. shocked, I tell you! that the USD is at Rs. 56 or 57 to the INR. In fact, is it completely predictable.. the exchange rate is simply the price of one currency in terms of another. Over the past 20 years, the USD has declined in purchasing power (as measured by inflation) by about 2% p.a. compounded. The INR has declined by about 7%. So what else would we expect? The law of Purchasing Power Parity (PPP) states that (over long enough periods), exchange rate changes track inflation differentials.. it makes perfect sense. The exchange rate has changed only 3% p.a over this period - we should count our blessings. It should have changed 5% (7 minus 2).. I confidently predict that, in 2023, the USD will be worth somewhere between Rs. 72 (if we continue the current average depreciation of 3%) and Rs. 85 (if we stick to the 5% difference in inflation).. in the long run, all exporters can take heart - the exchange rate is going to move in a positive direction - it simply has to, the law of PPP cannot be denied in the long run.