Yeah that's totally off topic LOL. CCP and CCCP are completely different and in many areas, CCP learned from the mistakes of the CCCP. CCCP's total GDP/resources never exceeded 10% of that of the US while China's is currently more than the US by PPP and about 2/3rds by nominal GDP. Totally different animal. Your fixation on nominal GDP per capita is really the least relevant measure to national power and development.
Looks stagnant to me right from 2008. Was doing good before that, not nearly as good as China, of course, but still pretty good. Any other Eastern European countries you wanted to pull up? LOL
Russia GDP PPP ( per capita purchase power parity ) was 55% of the USA in 1990, so I presume the CCCP was similar like that.
China is 28% of the USA at the moment.
Again, from tradingeconomics.
Your data about Poland showing the the performance modified by exchange rate, so a big jump / decrease of PLN/USD can change dramatically it, without any real change in the country performance.
I suggest this :
It filter out the exchange rate.
I have to point out that you use the GDP PPP when it fits your "need", and for the same calculation the GDP $ number when its fits your "need" : P
However generally the GDP performance of Poland doesn't show the disastrous job that the polish politicians done between 1980-2012.
The population well being is not equal with the GDP growth.