경제협력개발기구(OECD) 회원국을 놓고 보면, 제도 도입 여부가 확인되는 24개국의 경우 미국·영국 등 15개국은 허용하고, 독일·일본 등 9개국은 금지하는 등 뒤섞여 있다.
In terms of members of the Organization for Economic Cooperation and Development (OECD), in case of 24 countries that can ascertain whether the system introduced or not, 15 countries including the US and Britain are allowed to adopt the system and nine countries such as Germany and Japan are banned.