YOU SAID:

They work a lot better than they did fifteen years ago.

INTO JAPANESE

彼らは15年前よりもずっとよく働いています。

BACK INTO ENGLISH

They work much better than 15 years ago.

INTO JAPANESE

彼らは15年前よりもはるかにうまく機能します。

BACK INTO ENGLISH

They work much better than 15 years ago.