A financial guaranty insurer's outstanding total liability for municipal obligation bonds, special revenue bonds, and industrial development bonds shall be investment grade to the following extent: For financial guaranty insurers rated AAA by a nationally recognized statistical rating organization, at least 95 percent; For financial guaranty insurers rated AA by a nationally recognized statistical rating organization, at least 85 percent; and For financial guaranty insurers rated A by a nationally recognized statistical rating organization, at least 70 percent. By written request of a financial guaranty insurer, the Commissioner may approve any other level considered appropriate.