Final answer:
The number of life insurers has declined sharply due to company mergers and acquisitions, demutualization of insurers, and formation of mutual holding companies.
Step-by-step explanation:
The number of life insurers has declined sharply during the past decade due to all of the above factors: increase in company mergers and acquisitions, demutualization of insurers, and formation of mutual holding companies.
Company mergers and acquisitions lead to consolidation in the industry, resulting in a decrease in the number of individual insurers. Demutualization, which is the process of converting a mutual insurance company into a publicly-traded company, has also contributed to the decline in the number of life insurers. Additionally, the formation of mutual holding companies has led to mergers and combinations of insurance entities, further reducing the overall number of insurers.