For the year ended December 31, 2023, the average balance of interest-earning assets grew by $30.7 million, or 2.5%, to $1.24 billion and the average yield improved by 87 basis points to 4.88%, when compared to the year ended December 31, 2022. The average balance of interest-bearing liabilities increased by $76.4 million, or 9.0%, and the cost of interest-bearing liabilities increased by 165 basis points to 2.44%. The overall interest rate spread decreased by 78 basis points to 2.44% for the year ended December 31, 2023.
The provision for credit losses on loans decreased by $72,000, from $302,000 for the quarter ended December 31, 2022 to $230,000 for the current quarter. The provision for credit losses on loans increased $288,000, from $1.4 million for the year ended December 31, 2022 to $1.7 million for the year ended December 31, 2023. The decrease to the provision for the three months ended December 31, 2023 was primarily attributable to decreased loan production during the quarter. The increase to the provision for the year ended December 31, 2023 was primarily attributable to an increase in loan balances and changes to qualitative factors in response to changing economic conditions.
Net charge-offs decreased $205,000 from $851,000 for the fourth quarter of 2022 to net charge-offs of $646,000 for the fourth quarter of 2023. The decrease was primarily due to a commercial loan charge off in the fourth quarter of 2022 of $449,000. Net charge-offs increased $1.1 million from $1.0 million for the year 2022 to $2.1 million for the year 2023. The increase was primarily due to a $710,000 charge-off of one commercial loan in the second quarter of 2023 and increased net charge-offs in indirect automobile loans of $642,000. The percentage of overdue account balances to total loans decreased to 1.90% as of December 31, 2023 from 2.29% as of December 31, 2022, while non-performing assets decreased $217,000, or 4.9%, to $4.2 million at December 31, 2023.
Non-interest income totaled $1.4 million for the three months ended December 31, 2023, an increase of $107,000, or 8.3%, from the comparable period in the prior year, due primarily to a gain on the disposal of premises and equipment of $10,000 as opposed to a loss of $38,000 in the fourth quarter of 2022 and an increase in other non-interest income.
Non-interest income totaled $5.8 million for the year ended December 31, 2023, a decrease of $116,000, or 2.0%, from the comparable period in the prior year, due primarily to a decrease in the net gain on sales of mortgage loans as activity decreased due to fewer originations in the increasing interest rate environment and a strategic decision to hold new production in our portfolio instead of selling these loans. Gain on sales of mortgage loans decreased $746,000, or 86.3%, compared to the prior year as we sold $4.8 million of residential mortgage loans in the year 2023 as compared to $23.8 million in 2022. Investment advisory income decreased $69,000, or 5.6%, primarily the result of a challenging investment market and economic conditions. These decreases were partially offset by a $221,000 gain on life insurance, the prior year period net realized loss on the sale of securities of $170,000 and a $148,000 increase in other non-interest income as the income from mortgage servicing rights increased.
For the fourth quarter of 2023, non-interest expense totaled $9.1 million, a decrease of $471,000, or 4.9%, over the comparable 2022 period. The decrease was primarily due to a decrease in salaries and benefits of $612,000, or 11.8%, as the number of employees decreased due to a Company-wide reduction in force of approximately 5%. Occupancy expense decreased $148,000, or 12.4%, due to a branch closure at the end of 2022. These decreases were partially offset by an impairment charge of $375,000 in the fourth quarter of 2023, as we entered into an agreement for the property sale of our Beacon Branch in Wappingers Falls, NY. The sale is expected to close in the first quarter of 2024. Data processing fees and insurance expense both increased by $75,000 and $81,000, respectively.