Not an expert!
Something is odd with the numbers then. The displayed graph is GDP over time and they intersect by the end of it are around 20Billions. GDP per capita (without parity and so on...) is GDP/population if im not mistaken. Having the Yemeni population at around 4 to 5 times the lebanese one GDP per capita should be lower for yemen by the same factor.True , gdp per capita is a better indicator, where yemen is also better than lebanon.
Anyway i think the numbers are not correct because who can correctly estimate the GDP of a country without a real currency and where fraud is widespread with undeclared cash under the mattresses add to that an opaque central bank that still claims that everything is under control .... I hope this is rock bottom but i doubt it is. We desperately need a read audit.