Why do the Whites attribute scamming to Nigeria.

Sometimes i wonder why the white people attribute scamming to Nigeria. Its as if the only thing some of them know about Nigeria is that we are scammers. I agree that some Nigerian boys have tarnished our image via online dating, online business but their numbers are very very small compared to our population, but the fact is that there are scammers all over the world and the whites are not even exempted. And from my personal experience, there are more scammers in USA, UK, India, Pakistan, Albania, Romania etc than Nigeria but these nations are not projected as scammers. Is it because they are white and we are black? Is racism the reason? Let us hear your opinion on this please.