We earned $0.90 per share despite some revenue headwinds arising from pandemic-related delays in some areas and projects.
Our sequential backlog increased by $180 million this quarter on a same-store basis, and our year-over-year same-store backlog also increased by $200 million.
Revenue for the 2021 second quarter was $714 million, a decrease of $30 million compared to last year and our same-store revenue declined by $46 million.
Gross profit this quarter was $126 million, lower by $19 million.
And gross profit as a percentage of revenue declined to 17.7% this quarter compared to 19.6% for the second quarter of 2020.
If you compare the six months period this year to the same period in 2020, gross profit was 18.1% for the first six months of 2021, which is roughly equivalent to 18.2% for the first half of 2020.
SG&A expense for the quarter was $88 million, or 12.3% of revenue compared to $85 million, or 11.4% of revenue for the same quarter in 2020.
On a same-store basis, SG&A was similar to last year with a same-store increase of $1 million.
Our 2021 tax rate was 23.8% compared to 27.6% in 2020.
Net income for the second quarter of 2021 was $33 million, or $0.90 per share.
And that resulted -- that result included $0.10 of income related to the revaluation of our contingent earn-out obligations.
Our net income for the second quarter of 2020 was $39 million, or $1.08 per share.
For our second quarter, EBITDA was $55 million and year-to-date we have $106 million of EBITDA.
Free cash flow in the first six months was $101 million as compared to $151 million for the first half of 2020.
Amteck will be included in our Electrical segment, and it is expected to contribute annualized revenues of approximately $175 million to $200 million and EBITDA of $14 million to $17 million.
In light of the required amortization expense related to intangibles and other costs associated with that transaction, the acquisition is expected to make a neutral to slightly accretive contribution to earnings per share for the first 12 months to 18 months.
Backlog at the end of the second quarter of 2021 was $1.84 billion.
We believe that the business impacts relating to COVID-19 have now stabilized, and as a result same-store backlog increased sequentially by 11% or $180 million.
Our industrial activities were 42% of total revenue in the first half of 2021.
Institutional markets, which include education, healthcare and the government, are strong and with 33% of our revenue.
But with our changing mix it is now about 25% of our revenue.
For the first six months of 2021, construction was 77% of our revenue with 46% from construction projects for new buildings, and 31% from construction projects in existing buildings.
Service was a great story this quarter, and service revenue was 23% of year-to-date revenue with service projects providing 9% of revenue, and pure service, including hourly work, providing 14% of revenue.
Year-to-date service revenue is up approximately 12% with improved profitability.
Our Electrical gross margins improved from 6.5% in the first six months of 2020 to 14.3% this year.

Summary:
We earned $0.90 per share despite some revenue headwinds arising from pandemic-related delays in some areas and projects.
Net income for the second quarter of 2021 was $33 million, or $0.90 per share.