Excluding the effect of fuel, the 2021 OG&A Adjusted Items and the 2020 OG&A Adjusted Items, our OG&A rate decreased 95 basis points in the first two quarters of 2021, compared to the first two quarters of 2020. This decrease resulted primarily from decreased COVID-19 related costs, lower contributions to multi-employer pension plans, decreased incentive plan costs and broad-based improvement from cost savings initiatives that drive administrative efficiencies, store productivity and sourcing cost reductions, partially offset by the effect of supermarket sales deleverage, excluding fuel, due to cycling COVID-19 trends which increases our OG&A expense, as a percentage of sales.
Rent Expense
Rent expense remained consistent, as a percentage of sales, in both the second quarter and first two quarters of 2021, compared to the same periods in 2020.
Depreciation and Amortization Expense
Depreciation and amortization expense remained consistent, as a percentage of sales, in both the second quarter and first two quarters of 2021, compared to the same periods in 2020.
Operating Profit and FIFO Operating Profit
Operating profit was $839 million, or 2.65% of sales, for the second quarter of 2021, compared to $820 million, or 2.69% of sales, for the second quarter of 2020. Operating profit, as a percentage of sales, decreased 4 basis points in the second quarter of 2021, compared to the second quarter of 2020, due to reduced sales to retail customers without fuel and a lower gross margin rate, partially offset by decreased OG&A expense, as a percentage of sales, and increased fuel earnings.
Operating profit was $1.6 billion, or 2.25% of sales, for the first two quarters of 2021, compared to $2.1 billion, or 2.98% of sales, for the first two quarters of 2020. Operating profit, as a percentage of sales, decreased 73 basis points in the first two quarters of 2021, compared to the first two quarters of 2020, due to reduced sales to retail customers without fuel as we cycle prior year COVID-19 trends, a lower gross margin rate, increased depreciation and amortization expense, as a percentage of sales, and decreased fuel earnings, partially offset by decreased OG&A expense, as a percentage of sales.
FIFO operating profit was $886 million, or 2.80% of sales, for the second quarter of 2021, compared to $843 million, or 2.76% of sales, for the second quarter of 2020. FIFO operating profit, as a percentage of sales, excluding the 2021 and 2020 Second Quarter Adjusted Items, increased 7 basis points in the second quarter of 2021, compared to the second quarter of 2020, due to decreased OG&A expense, as a percentage of sales, and increased fuel earnings, partially offset by reduced sales to retail customers without fuel and a lower gross margin rate.
FIFO operating profit was $1.7 billion, or 2.37% of sales, for the first two quarters of 2021, compared to $2.2 billion, or 3.05% of sales, for the first two quarters of 2020. FIFO operating profit, as a percentage of sales, excluding the 2021 and 2020 Adjusted Items, decreased 7 basis points in the first two quarters of 2021, compared to the first two quarters of 2020, due to reduced sales to retail customers without fuel as we cycle prior year COVID-19 trends, a lower gross margin rate, increased depreciation and amortization expense, as a percentage of sales, and decreased fuel earnings, partially offset by decreased OG&A expense, as a percentage of sales.
Specific factors contributing to the operating trends for operating profit and FIFO operating profit above are discussed earlier in this section.