EBITDA increased from $101 million in the third quarter of last year to $156 million this quarter, an increase of 54%. Free cash flow for the first 9 months of 2023 was a remarkable $402 million. We continue to benefit from advanced payments for work that we will need to fund and complete in upcoming quarters. Our trailing 12-month operating cash flow exceeds our trailing 12-month earnings by an astounding $300 million. That overcollection must reverse at some point as we pay to perform the work that we have already been paid for. But the timing is unknown, and it is dependent on the timing of future orders and future advanced payments. In the meantime, these collections have allowed us to lower our debt and our interest costs tremendously.
So far this year, we have spent $64 million on capital expenditures, which is double the amount we have spent at this time last year. The increase includes the build-out of 2 vast new modular production facilities and the purchase of vehicles as we catch up from COVID. Our substantial cash flow allowed us to pay down our revolving credit facility to 0 this quarter and to reduce our overall debt by $209 million since the year began. And during that time, we also funded the purchase of Eldeco from our current cash flow. We continue to purchase our shares and have acquired 64,000 so far this year at an average price of $134.53. Finally, as Brian mentioned, we acquired Decco at the beginning of October. We expect Decco to initially contribute annualized revenues of approximately $50 million to $65 million at margins that are consistent with our overall business.
They will be included in our mechanical segment. So I’ve got our financials, Brian.
Brian Lane: Okay. Thanks, Bill. I’m going to spend a few minutes discussing our business and outlook. Our backlog at the end of the third quarter was $4.3 billion. Since last year at this time, our same-store backlog has increased by $0.9 billion, around 27% with increases in our traditional mechanical and electrical business and substantial new bookings in our offsite construction operations. Our sequential backlog increased by $102 million despite the heavy revenue volume over the past 3 months. Our pipeline of future work remains strong. Our revenue mix continues to trend towards data centers, life science, food and other manufacturing such as chip plants and battery. Those industrial customers accounted for 54% of total revenue in the first 9 months of 2023, and they are major drivers of pipeline and backlog.
Technology, which is included in industrial was 21% of our revenue in the first 9 months of 2023, a substantial increase from 13% in the prior year. Institutional markets, which include education, health care and government are also strong and represent 27% of our revenue. The commercial sector is active, but with our changing mix, it is now a smaller part of our business at about 19% of revenue, and most of that commercial revenue is service. Year-to-date, construction was 80% of our revenue with projects for new buildings at 55%, while existing building construction was 25%. Service revenue increased by 14% year-to-date compared to last year. Service was 20% of our total revenues with service projects providing 9% of total revenue and pure service, including hourly work, providing 11% of revenue.
Service revenue continues to be about 20% of our total revenue and our service business is on track to be $1 billion of revenue for full year 2023. In both service and construction, we are encouraging in supporting our customers as they seek to improve the efficiency and sustainability of their buildings and operations. And we are committed to being good members of the diverse communities we serve. Comfort Systems is fortunate to have the right capabilities to help meet the surgi need for mechanical and electrical experts to grow data capacity for artificial intelligence and to help increase our country’s capacity to build its own chips, manufacture its own medicines, supply its batteries and provide health care resources as our population ages.
