This year will be our 20th statistical survey since we started doing it in the year 2000.
It's been 20 years since we started doing this statistical survey.
ーThis year will be our 20th statistical survey since we started doing it in the year 2000.
「２０００年に始めて以来、今年で２０回目の統計調査になります。」
「統計調査」は statistical survey
20th statistical survey で「２０回目の統計調査」
ーIt's been 20 years since we started doing this statistical survey.
「我々が統計調査を始めてから２０年になります。」
It's been 20 years since ... で「…以来２０年が経った」
このように現在完了形を使っても表現できます。
ご参考まで！
カナダ 
