Final answer:
The reference percentages provided do not match the options listed in the question about the average percentage of churn reduction by Pega Customer Decision Hub, and hence a correct answer cannot be determined.
Step-by-step explanation:
The question at hand is to determine the average percentage by which Pega Customer Decision Hub reduces churn each year. Reviewing the given reference percentages, we can see that these numbers don't align with the options provided in the question (10%, 15%, 20%, 25%).
Therefore, to accurately answer the question, we must decline as the data does not support any definitive conclusion regarding the specific average percentage of churn reduction by Pega Customer Decision Hub.
Hence, the answer is not provided among options.