and one CRJ900 aircraft under early lease buyouts for $142.4 million, of which $102.4 million was capitalized as fixed assets and $40.0 million was applied towards previously recorded lease liabilities.
Other operating expenses. Other operating expenses primarily consist of property taxes, hull and liability insurance, simulator costs, crew per diem, crew hotel costs and credit loss reserves. The $50.0 million, or 15.7%, decrease in other operating expenses primarily related to a non-cash impairment charge of $51.4 million in 2022 as a result of 14 CRJ700 aircraft that were classified as held for sale in 2022. We recorded an additional charge of $2.3 million related to these 14 CRJ700s in 2023 based on updated fair values.
Summary of interest expense, interest income, other income (expense) and provision for income taxes:
Interest Expense. The $3.8 million, or 3.0%, increase in interest expense was primarily related to higher fixed interest rates on debt issued since December 31, 2022, partially offset by a decrease in outstanding debt from $3.4 billion at December 31, 2022 to $3.0 billion at December 31, 2023. Our average effective interest rate for 2023 and 2022 was 4.1% and 4.0%, respectively.
Interest income. Interest income increased $26.3 million, from $17.6 million during the year ended December 31, 2022, to $43.9 million during the year ended December 31, 2023. Our interest income increased primarily from an increase in average interest rates attributed to our marketable securities for the year ended December 31, 2023, compared to the year ended December 31, 2022.
Other income (loss), net. Other income (loss), net increased $2.3 million in 2023, compared to 2022. Other income (loss), net primarily consists of the realized and unrealized gains or losses on our investments in other companies, income related to our investment in a joint venture with a third party and gains or losses on the sale of assets. The increase in other income (loss), net was primarily an increase in gains from the sale of assets, partially offset by a decrease in unrealized gains on our investments in other companies for the year ended December 31, 2023, compared to the year ended December 31, 2022.
Provision for income taxes. For the years ended December 31, 2023, and December 31, 2022, our income tax provision rates were 14.8% and 21.2%, respectively, which included the statutory federal income tax rate of 21% and other reconciling income tax items, including state income taxes and the impact of non-deductible expenses. For the year ended December 31, 2023, the decrease in our effective tax rate primarily related to a benefit of $7.6 million for the release of a previously recorded uncertain tax position liability and a $1.1 million benefit for the release of valuation allowance against certain deferred tax assets associated with state net operating losses with a limited carry forward period. Our income tax provision rate may fluctuate each reporting period based on various factors including, but not limited to, the amount of our non-deductible operating expenses, relative to our income before income taxes.
Net Income. Primarily due to the factors described above, we generated net income of $34.3 million, or $0.77 per diluted share, for the year ended December 31, 2023, compared to net income of $73.0 million, or $1.44 per diluted share, for the year ended December 31, 2022.
Our Business Segments 2023 compared to 2022:
Our reporting segments consist of (1) the operations of SkyWest Airlines and SWC, which had its first revenue generating flight in May 2023, (collectively, “SkyWest Airlines and SWC”) and (2) SkyWest Leasing activities.
Our chief operating decision maker analyzes the profitability of operating aircraft under our code-share agreements separately from the profitability of financing new aircraft acquired through debt and cash placed under our capacity purchase agreements, currently consisting of our E175 fleet, and our return on such aircraft financing. More specifically, the SkyWest Leasing segment includes an allocation of revenue from our capacity purchase agreements attributed to our financing of new aircraft through debt and cash covered under such agreements, and the respective depreciation and interest expense of such financed aircraft. The SkyWest Leasing segment also includes the activity of acquiring and leasing used regional jet aircraft and regional aircraft engines to other entities. The SkyWest Leasing segment’s total assets and capital expenditures include new E175 aircraft acquired through the issuance of debt and our aircraft and engines leased to other entities. Additionally, aircraft removed from SkyWest Airlines operations and held for sale are included in the SkyWest Leasing segment.