The occupation with the highest rate of smokers is ~
The job with the most smokers is ~
フォーマルにいうと：
'The occupation with the highest rate of smokers is ~'
occupation = 職業
the highest =一番高い
rate of smokers= 喫煙率
もっとインフォーマルか簡単にいうと
'The job with the most smokers is ~'
「一番喫煙者が多い仕事は～です。」
オランダ 
