The problem is that multiple 3rd party surveys including Russian, Chinese, western, and semi-western (ie Japanese) surveys report the same thing within margin of error.
At least for Russia, western survey results are in general agreement with domestic and Chinese survey results.
If they're lying specifically about Iran because it is more difficult to corroborate results even from Iranian organizations themselves, that is possible. But Iran has open elections too, with known results, and since 2013 they've been relatively consistent in voting for the pro west candidate. They've also been making baffling choices that don't make sense unless you conclude they're secretly pro west.
So I don't see a fundamental proof of a lie here. The number is at least plausible.