compensation, and $9,000 in telephone expense, partially offset by decreases of $55,000 in legal fees, $51,000 in miscellaneous other non-interest expense, $13,000 in insurance expense, $8,000 in directors, officers and employee expense, $5,000 in office supplies, and $1,000 in recruitment expenses related to the hiring of personnel.
Advertising expense increased by $9,000, or 33.3%, to $36,000 for the three months ended September 30, 2021 from $27,000 for the three months ended September 30, 2020 due mainly to the resumption of advertising and promotional products.
Occupancy expense increased by $9,000, or 1.9%, to $489,000 for the three months ended September 30, 2021 from $480,000 for the three months ended September 30, 2020 primarily as a result of the cost of operating additional office space.
Outside data processing expense decreased by $54,000, or 12.0%, to $395,000 for the three months ended September 30, 2021 from $449,000 for the three months ended September 30, 2020 due to additional services required in 2020.
There was no goodwill impairment expense for the three months ended September 30, 2021 compared to goodwill impairment expense of $50,000 for the three months ended September 30, 2020. The goodwill was recorded in connection with the acquisition of Harbor West Financial Planning Wealth Management Group in 2007, which is operated as a division of Northeast Community Bank. The goodwill impairment was caused primarily by the expected decrease in revenue from this division due to a decrease in clients and the resulting decrease in assets under management.
Real estate owned expense decreased by $16,000, or 47.1%, to $18,000 for the three months ended September 30, 2021 from $34,000 for the three months ended September 30, 2020 due to a reduction in operating expenses to maintain the one real estate owned property.
Income Taxes. We recorded income tax expense of $265,000 and $956,000 for the three months ended September 30, 2021 and 2020, respectively. For the three months ended September 30, 2021, we had approximately $185,000 in tax exempt income, compared to approximately $166,000 in tax exempt income for the three months ended September 30, 2020. Our effective income tax rates were 26.6% and 23.4% for the three months ended September 30, 2021 and 2020, respectively.
Results of Operations for the Nine Months Ended September 30, 2021 and 2020
Financial Highlights
Net income for the nine months ended September 30, 2021 was $7.7 million compared to net income of $8.9 million for the nine months ended September 30, 2020. Net income for the nine months ended September 30, 2021 was lower than net income for the nine months ended September 30, 2020 primarily due to an increase in the provision for loan losses expense, an increase in non-interest expense, and a decrease in non-interest income. These were partially offset by an increase in the net interest income and a decrease in income tax expense.
Net Interest Income
Net interest income totaled $31.6 million for the nine months ended September 30, 2021, as compared to $28.8 million for the nine months ended September 30, 2020. The increase in net interest income of $2.9 million, or 10.0%, was primarily due to the decrease in interest expense that exceeded a decrease in interest income. In a manner consistent with the decrease in interest rates in response to the COVID-19 pandemic, our cost of interest bearing liabilities decreased much greater than our yield on interest earning assets as our interest bearing liabilities repriced much faster to lower interest rates than our yield on interest earning assets.
Interest and dividend income decreased by $1.4 million, or 3.8%, to $35.6 million for the nine months ended September 30, 2021 from $37.0 million for the nine months ended September 30, 2020 due to a decrease in the yield on interest earning assets by 65 basis points from 5.64% for the nine months ended September 30, 2020 to 4.99% for the nine months ended September 30, 2021, partially offset by an increase in the average balance of interest earning assets of