First iPhone ever released $400 (June 2007)
10 years later
iPhone 8 cost $700
iPhone X cost $1000
take average of these 2.
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I'd say its a pretty accurate inflation indicator
Every time you make those kind of exercises you see the real inflation, I have keep track of the price of milk in my country and I get similar results, according to our government the inflation is something like 3% or 4% per year but when I track the price of milk I get something close to 10% per year, you can do this with almost any product and you will get the same results in my country.