Annuity product charges (surrender charges assessed against policy withdrawals and fees deducted from policyholder account balances for lifetime income benefit riders) increased 27% to $173.6 million in 2016 and 14% to $136.2 million in 2015 from $119.0 million in 2014. The components of annuity product charges are set forth in the table that follows:
Amortization of deferred sales inducements, in general, has been increasing each year due to growth in our annuity business and the deferral of sales inducements incurred with respect to sales of premium bonus annuity products. Bonus products represented 88%, 89% and 89% of our net annuity deposits during 2016, 2015 and 2014, respectively. The increases in amortization from these factors have been affected by amortization associated with (1) fair value accounting for derivatives and embedded derivatives utilized in our fixed index annuity business, (2) net realized gains (losses) on investments and net OTTI losses recognized in operations and (3) changes in litigation reserves. Fair value accounting for derivatives and embedded derivatives utilized in our fixed index annuity business creates differences in the recognition of revenues and expenses from derivative instruments including the embedded derivative liabilities in our fixed index annuity contracts. The change in fair value of the embedded derivatives will not correspond to the change in fair value of the derivatives (purchased call options), because the purchased call options are one-year options while the options valued in the fair value of embedded derivatives cover the expected lives of the contracts which typically exceed ten years. Amortization of deferred sales inducements is summarized as follows:
Other operating costs and expenses increased 6% to $102.2 million in 2016 and increased 18% to $96.2 million in 2015 from $81.6 million in 2014 and are summarized as follows:
We have determined that the unrealized losses of the securities on the watch list are temporary as we do not intend to sell these securities and it is more likely than not we will not have to sell these securities before recovery of their amortized cost. Our analysis of these securities and their credit performance at December 31, 2016 is as follows:
Currently, American Equity Life may pay dividends or make other distributions without the prior approval of the Iowa Insurance Commissioner, unless such payments, together with all other such payments within the preceding twelve months, exceed the greater of (1) American Equity Life's net gain from operations for the preceding calendar year, or (2) 10% of American Equity Life's statutory capital and surplus at the preceding December 31. For 2017, up to $272.7 million can be distributed as dividends by American Equity Life without prior approval of the Iowa Insurance Commissioner. In addition, dividends and surplus note payments may be made only out of statutory earned surplus, and all surplus note payments are subject to prior approval by regulatory authorities in the life subsidiary's state of domicile. American Equity Life had $1.4 billion of statutory earned surplus at December 31, 2016.
Our fixed maturity securities (bonds and redeemable preferred stocks maturing more than one year after issuance) and equity securities classified as available for sale are reported at fair value. Unrealized gains and losses, if any, on these securities are included directly in stockholders' equity as a component of accumulated other comprehensive income (loss), net of income taxes and certain adjustments for assumed changes in amortization of deferred policy acquisition costs and deferred sales inducements. Unrealized gains and losses represent the difference between the amortized cost or cost basis and the fair value of these investments. We use significant judgment within the process used to determine fair value of these investments.