From Longman Dictionary of Contemporary Englishbe down to somebody/somethingbe down to somebody/somethingRESULTto be the result of one person’s actions or one particular thing Chris’s success is all down to him. → down
Examples from the Corpus
be down to somebody/something• 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.• Of course, much of this is down to familiarity - knowing where the goal posts are.• Say it was down to fifty.• 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.