Our third-quarter performance highlighted the exceptional cash generation capability of our business model as we generated nearly $1.2 billion of cash from operations.
This burst of inflation accelerated through the third quarter, and during the quarter, we saw roughly $60 million of labor inflation and about $100 million of inflation in other operating cost categories.
Overall, our underlying labor inflation for the third quarter was 8.7%.
Our pricing programs delivered core price of 4.6% and collection and disposal yield of 3.5% in the third quarter.
Standout performance continues to be the residential line of business with a yield of 5%, while MSW yield improved to 3.5%.
But keep in mind, the price escalations on about 40% of our revenue are tied to an index, often based on a look-back over the prior year, so there's a timing lag in adjusting index pricing when costs step up as quickly as they have.
And it's important to understand that a portion of the remaining 60% of our business won't get the full 7% to 10% price increases we believe we need to cover rising costs until their next price increase cycle.
A customer who has increased 4% in May won't get the full cost recovery price increase until next May.
Given the success of these rebuilds and the labor inflation challenges of late, we've accelerated the retooling of the remaining single-stream plants and expect to address 90% of single-stream volume by the 2023-2024 time frame.
Of note, our focus on unlocking more plastic from the waste stream drove a 25% increase in plastics we recycle since 2019.
Our team continues to execute very well despite a challenging operating environment, producing more than 7% organic revenue growth in collection and disposal business in the third quarter.
This growth, combined with continued integration of Advanced Disposal, drove operating EBITDA more than 14% higher.
Adjusted operating expenses as a percentage of revenue increased 180 basis points to 62.2% in the third quarter as we experienced pressure from inflationary costs, supply chain constraints and stronger-than-expected volume growth.
In the residential line of business, we continue to work through the last 40% of our routes, including those from ADS that are not fully automated while continuing to be very selective in the business we are willing to take on, as evidenced by our yield and volume results in the third quarter and the last few years.
Turning to our strong revenue results, third-quarter collection and disposal volume grew by 3.8%, which outpaced our expectations.
We continue to see strong volume, driven by economic reopening with commercial volume up 4.6% and special waste volume up by 16.6%, and we see runway for continued solid performance in the fourth quarter.
Service increases outpaced service decreases by more than twofold for the second consecutive quarter and churn was 8.7%.
Year to date, net new business for small and medium business customers is up more than 10%.
We've combined around 70% of the acquired operations into our billing and operational systems, and we remain on track to migrate virtually all the ADS customers by the end of the year.
We've achieved nearly $26 million in annual run rate synergies during the third quarter, bringing the year-to-date total to $60 million.
Combined with the $15 million of annual run rate synergies realized in the fourth quarter of 2020, we're on track to reach $100 million by the end of the year.
And we continue to forecast another $50 million to be captured in 2022 and 2023 from a combination of cost and capital savings.
Total company revenue growth is now expected to be between 17% and 17.5%, with yield and volume in our collection and disposal business of about 6.5%.
We're confirming our most recent 2021 adjusted operating EBITDA guidance of between $5 billion and $5.1 billion, which is an increase from the prior year of about 17% at the midpoint and almost 5% higher than our initial outlook for the year.
Third-quarter SG&A was 9.7% of revenue, a 40-basis-point improvement over 2020.
Included in our results is about $16 million of increased digital investments as we advanced technology that will benefit customer engagement and lower our cost to serve over the long term.
Third-quarter net cash provided by operating activities was $1.18 billion, an increase of 15%.
In the third quarter, capital spending was $464 million, bringing capital expenditures in the first nine months of the year to $1.13 billion.
Investments in recycling technology and equipment at our MRFs are expected to be about $200 million for the year.
While we continue to target full-year capital spending at the low end of our $1.78 billion to $1.88 billion guidance range, we could see 2021 coming in below targeted levels, with some of our spending pushed into 2022, primarily due to supply chain constraints.
We generated $773 million of free cash flow in the third quarter.
And through September, our business generated free cash flow of $2.29 billion, seeing us well on our way to our full-year targeted free cash flow of $2.5 billion to $2.6 billion.
We've returned more than $1.7 billion to our shareholders through the first nine months, paying $730 million in dividends and repurchasing $1 billion of our stock.
We continue to expect to repurchase up to our full authorization of $1.35 billion in 2021.
Our leverage ratio at the end of the quarter was 2.71 times as the strength of our business performance and the successful integration of the acquired ADS business drove the achievement of our targeted leverage ratio ahead of plan.

Summary:
Total company revenue growth is now expected to be between 17% and 17.5%, with yield and volume in our collection and disposal business of about 6.5%.
We're confirming our most recent 2021 adjusted operating EBITDA guidance of between $5 billion and $5.1 billion, which is an increase from the prior year of about 17% at the midpoint and almost 5% higher than our initial outlook for the year.