Adjusted Operating Income - Insurance
Adjusted Operating Income ("Insurance AOI") and Pre-tax Adjusted Operating Income (“Pre-tax Insurance AOI”) for the Insurance segment are non-U.S. GAAP financial measures frequently used throughout the insurance industry and are economic measures the Insurance segment uses to evaluate its financial performance. Management believes that Insurance AOI and Pretax Insurance AOI measures provide investors with meaningful information for gaining an understanding of certain results and provide insight into an organization’s operating trends and facilitates comparisons between peer companies. However, Insurance AOI and Pre-tax Insurance AOI have certain limitations, and we may not calculate it the same as other companies in our industry. It should, therefore, be read together with the Company's results calculated in accordance with U.S. GAAP.
Similarly to Adjusted EBITDA, using Insurance AOI and Pre-tax Insurance AOI as performance measures have inherent limitations as an analytical tool as compared to income (loss) from operations or other U.S. GAAP financial measures, as these non-U.S. GAAP measures exclude certain items, including items that are recurring in nature, which may be meaningful to investors. As a result of the exclusions, Insurance AOI and Pre-tax Insurance AOI should not be considered in isolation and do not purport to be an alternative to income (loss) from operations or other U.S. GAAP financial measures as measures of our operating performance.
Management defines Pre-tax Insurance AOI as Insurance AOI adjusted to exclude the impact of income tax (benefit) expense recognized during the current period. Management believes that Insurance AOI and Pre-tax Insurance AOI provide meaningful financial metrics that help investors understand certain results and profitability. While these adjustments are an integral part of the overall performance of the Insurance segment, market conditions impacting these items can overshadow the underlying performance of the business. Accordingly, we believe using a measure which excludes their impact is effective in analyzing the trends of our operations.
The table below shows the adjustments made to the reported Net income (loss) of the Insurance segment to calculate Insurance AOI and Pre-tax Insurance AOI (in millions). Refer to the analysis of the fluctuations within the results of operations section:
(1) The Insurance segment revenues are inclusive of realized and unrealized gains and net investment income for the year ended December 31, 2019 and 2018. Such adjustments are related to transactions between entities under common control which are eliminated or are reclassified in consolidation.
Net income for the year ended December 31, 2019 decreased $105.8 million to $59.4 million from $165.2 million for the year ended December 31, 2018. Pre-tax Insurance AOI for the year ended December 31, 2019 increased $85.1 million to $85.7 million from $0.6 million for year ended December 31, 2018. The increase was primarily driven by the incremental net investment income and policy premiums from the KIC block acquisition and higher net investment income from the legacy CGI block driven by both the growth and mix of the investment portfolio, including premium reinvestment and rotation into higher yield assets. In addition, there was a decrease in policy benefits, changes in reserves, and commissions related to current period reserve adjustments driven by higher mortality and policy terminations, an increase in contingent non-forfeiture option activity as a result of in-force rate actions approved and implemented, and favorable developments in claims activity. This was partially offset by an increase in selling, general and administrative expenses, primarily attributable to headcount additions related to the KIC acquisition.
Table:
 |  | Year ended December 31, | 
 |  |  | Increase /
 | 2019 | 2018 | (Decrease)
Net income - Insurance segment | $59.4 | $165.2 | $(105.8)
Effect of investment (gains) (1) | (1.9) | (5.6) | 3.7
Asset impairment expense | 47.3 | — | 47.3
Gain on bargain purchase | (1.1) | (115.4) | 114.3
Gain on reinsurance recaptures | — | (47.0) | 47.0
Acquisition costs | 2.1 | 2.8 | (0.7)
Insurance AOI | 105.8 | — | 105.8
Income tax expense (benefit) | (20.1) | 0.6 | (20.7)
Pre-tax Insurance AOI | $85.7 | $0.6 | $85.1


Question: What was the increase / (decrease) in the effect of investment gains from 2018 to 2019?
Answer: 3.7