From Longman Dictionary of Contemporary Englishbe down to somebodybe down to somebodyRESPONSIBLEif an action or decision is down to you, it is your responsibility It’s down to me to make sure that everyone is happy. → be up to somebody at up1 → down
Examples from the Corpus
be down to somebody• By his calculations he was down to $ 12,006.• However, monthly inflation, which had reached 123 percent in February, was down to 5 percent by May-June.• By 1970, about 20 percent of the land in cultivation was down to export crops.• Of course, much of this is down to familiarity - knowing where the goal posts are.• Her garters were down to her ankles.• Attendances were down to one million per week.• A few students had left; the class was down to twelve or thirteen. 