Our assets decreased $29 million from 2017 to 2018 and totaled $1.6 billion as of December 31, 2018.
Insurance premiums decreased 5.0% in 2018 and 0.1% in 2017, respectively, primarily from our Life Insurance segment, which decreased $9.6 million from 2017.
Policyholder Dividends. The Company issues long duration participating policies in our Life segment to foreign residents that are expected to pay dividends to policyholders based upon actual experience. Initially, policyholder dividend scales are factored into the guaranteed premiums at the time the product is developed, based on expected future experience and desired profit goals. As actual and expected experience develops over time, it can become necessary to adjust dividends, as we did at the end of 2015 when our expense to policyholders was $10.7 million, in order to maintain long term product profitability. Policyholders' dividends have remained relatively consistent at $6.4 million, $6.3 million and $6.8 million in 2018, 2017, and 2016, respectively.
Amortization of Cost of Customer Relationships Acquired ("COIA"). Amortization of COIA increased in 2018 due to an update in our Home Service segment assumptions that resulted in a true up adjustment of approximately $663,000.
Realized Investment Gains (Losses), Net. This segment recognized losses on other-than-temporary impairments totaling $0.2 million in 2018 and 2017 and $2.0 million in 2016, related to bond and mutual fund holdings. A gain of $1.1 million was recognized on the sale of real estate property in 2017.
Amortization of Cost of Customer Relationships Acquired. Amortization of COIA increased in 2018 compared to 2017 due to an update in our assumptions that resulted in a true up adjustment of approximately $663,000.
The tables below represent the Company’s detailed exposure to municipal holdings in Texas and Florida, which comprise the most significant state concentrations of the total municipal fixed maturity portfolio as of December 31, 2018.
Our liquidity requirements are met primarily by funds provided from operations. Premium deposits and revenues, investment income and investment maturities are the primary sources of funds, while investment purchases, policy benefits, and operating expenses are the primary uses of funds. We historically have not had to liquidate investments to provide cash flow, and there were no liquidity issues in 2018 or 2017. Our investments consist of 91.7% of marketable debt securities classified as available-for-sale and 1.1% of equity securities that could be readily converted to cash for liquidity needs.
excess cash held at the end of 2015. The Company's cash flows from financing activities were $0.1 million, $2.5 million and $2.5 million in 2018, 2017 and 2016, respectively.
The NAIC has established minimum capital requirements in the form of RBC. RBC considers the type of business written by an insurance company, the quality of its assets, and various other aspects of an insurance company's business to develop a minimum level of capital called "Authorized Control Level Risk-based Capital" and compares this level to an adjusted statutory capital that includes capital and surplus as reported under statutory accounting principles, plus certain investment reserves. Should the ratio of adjusted statutory capital to control level risk-based capital fall below 200%, a series of remedial actions by the affected company would be required. We have a parental guarantee between Citizens Inc. and CICA to maintain a RBC level above 350%.