Production taxes. Our production taxes decreased by $3.4 million (109%) to a credit (income) of $0.3 million for the three months ended June 30, 2020 from $3.1 million for the prior year period, which was driven by our overall decrease in revenue and a severance tax refund from prior periods of at least $1.1 million that the Company expects to receive. Exclusive of the expected severance tax refund, production taxes decreased to 5.7% of total revenue for the three months ended June 30, 2020, as compared to 5.9% of total revenue for the three months ended June 30, 2019.
Our production taxes decreased by $4.5 million (72%) to $1.7 million for the six months ended June 30, 2020 from $6.2 million for the prior year period, which was also driven by our overall decrease in revenue and the aforementioned severance tax refund. Exclusive of the expected severance tax refund, production taxes decreased to 6.1% of total revenue for the six months ended June 30, 2020, as compared to 6.2% of total revenue for the six months ended June 30, 2019.
Depletion, depreciation and amortization expense (“DD&A”). Our DD&A expense related to proved oil and natural gas properties decreased by $2.6 million (11%) to $20.2 million for the three months ended June 30, 2020 from $22.8 million for the prior year period. On a per Boe basis, DD&A increased to $26.15 per Boe for the three months ended June 30, 2020 compared to $18.05 per Boe for the prior year period. DD&A per Boe for the three months ended June 30, 2019, was diluted by production from the Dimmit County assets, which were classified as held for sale and not subject to depletion. The assets were sold in October 2019.
For the six months ended June 30, 2020, DD&A expense related to proved oil and natural gas properties of $44.4 million was relatively flat as compared to the same prior year period. On a per Boe basis, DD&A increased to $25.13 per Boe for the six months ended June 30, 2020 compared to $18.63 per Boe for the prior year period for the reason noted above.
Impairment expense. We did not record any impairment expense during the three months or six months ended June 30, 2020. During the three and six months ended June 30, 2019, we recorded impairment expense of $5.8 million and $9.1 million related to our Dimmit County oil and gas properties, which were classified as held for sale as of June 30, 2019 and subsequently divested in October 2019.
Reserve estimates and related impairments of proved and unproved properties are difficult to predict in a volatile price environment. Due to the supply impacts associated with the competition between Russia and Saudi Arabia for crude oil market share and demand impacts associated with the global COVID-19 pandemic, we may experience proved or unproved property impairments in the future if commodity prices for the products we produce continue to decline, if we experience changes to our longer term development plans or if there are downward adjustments to our reserves.
General and administrative expense (“G&A”). G&A decreased by $1.5 million (27%) to $4.0 million for the three months ended June 30, 2020 as compared to $5.4 million for the prior year. During the three months ended June 30, 2020 we incurred legal and advisory fees of $0.6 million ($0.83 per Boe) to amend our credit agreements and comply with certain covenants, including negotiations with the lenders under our credit agreements to reduce the our total debt and leverage and explore transactions to increase the our capital. During the three months ended June 30, 2019 we incurred legal and accounting fees to complete our Redomiciliation to the U.S of $0.5 million ($0.38 per Boe). G&A, excluding the costs associated with these discrete transactions, decreased on an absolute basis as compared to prior year primarily due to lower salaries and wages as a result of the expected PPP loan forgiveness of $0.8 million attributable to the three months ended June 30, 2020 and our workforce reduction of approximately 18% and also reduced salaries for certain positions, which occurred in early May 2020.
For the six months ended June 30, 2020, G&A decreased by $1.2 million (11%) to $9.5 million as compared to $10.7 million for the same prior year period. During the six months ended June 30, 2020 we incurred legal and advisory fees of $0.6 million ($0.36 per Boe) related to the credit facility amendments as described above and $0.2 million ($0.12 per Boe) for legal and accounting fees to complete our Redomiciliation to the U.S. During the six months ended June 30, 2019 we incurred legal and accounting fees related to the Redomiciliation of $1.0 million ($0.43 per Boe). G&A, excluding the costs associated with these discrete transactions, decreased on an absolute basis as compared to prior year primarily due to lower salaries and wages as a result of the expected PPP loan forgiveness of $0.8 million attributable to the six months ended June 30, 2020 and our workforce and salary reductions.