During the third quarter, we delivered revenue and EBITDA growth of approximately 14% compared to the prior year.
Generated adjusted earnings per share of $1.11, which represents an increase of 11% over the prior year and produced $1.4 billion of adjusted free cash flow on a year-to-date basis.
Year-to-date, we've invested over $900 million in acquisitions to further enhance our market position and increase free cash flow.
On August 31, we completed the acquisition of ACV Enviro.
We now expect to invest over $1 billion in acquisitions through the full year.
In addition to investing in acquisitions, we have returned $622 million to our shareholders through dividends and share repurchases.
Our customer retention rate remains at a record-setting level of 95%.
Total core price remained at an all-time high of 5.2%, and average yield increased to 3.2%.
Volume increased 4.3% compared to the prior year, which exceeded our expectations.
And acquisitions contributed an incremental 350 basis points to total revenue growth.
We have now implemented tablets in approximately 70% of our large and small container fleet.
We currently have 17 projects in the pipeline with more opportunities thereafter.
This project consists of 30,000 solar panels and will produce enough energy to power 2,200 homes annually.
We remain committed to increasing the recycling and circularity of key materials as part of our ambitious 2030 sustainability goal.
Accordingly, we are increasing 2021 full year financial guidance as follows: adjusted earnings per share is now expected to be in the range of $4.10 to $4.13; and adjusted free cash flow is now expected to be in the range of $1.475 billion to $1.5 billion.
Core price during the third quarter was 5.2%, which included open market pricing of 6.5% and restricted pricing of 2.9%.
The components of core price included small container of 8.2%, large container of 5% and residential of 5%.
Average yield was 3.2%, which increased 60 basis points from the second quarter.
Third quarter volume increased 4.3%.
The components of volume included an increase in small container of 5.4%, an increase in large container of 3.9% and an increase in landfill of 6.6%.
Commodity prices increased to $230 per ton in the third quarter.
This compares to $99 per ton in the prior year.
Recycling processing and commodity sales contributed 160 basis points to internal growth during the third quarter.
Third quarter Environmental Solutions revenue increased $27 million from the prior year.
On a same-store basis, environmental solutions contributed 20 basis points to internal growth during the third quarter.
Adjusted EBITDA margin for the third quarter was 30.4%, and increased 10 basis points over the prior year.
This included a 90 basis point increase from recycled commodity prices, a 50 basis point headwind from net fuel and a 30 basis point headwind from the impact of recent acquisitions, primarily driven by deal and integration costs.
SG&A was 10.2% of revenue.
This represents an increase of 20 basis points over the prior year, which was exclusively due to higher incentive compensation accruals.
Year-to-date adjusted free cash flow was $1.4 billion and increased $247 million or 22% compared to the prior year.
It should also be noted that we increased our expected full year capital spending in our upwardly revised guidance by over $50 million.
Free cash flow conversion through September continued to track ahead of our original expectations and increased 330 basis points over the prior year.
During the quarter, total debt was $9.3 billion, and total liquidity was $2.4 billion.
Interest expense decreased $11 million due to refinancing activities completed last year, and our leverage ratio was 2.8 times.
With respect to taxes, our third quarter adjusted effective tax rate was 25.5%.
We had an equivalent tax impact of 27% when you include noncash charges from solar investments.
We expect our fourth quarter equivalent tax impact to be approximately 25%.

Summary:
Generated adjusted earnings per share of $1.11, which represents an increase of 11% over the prior year and produced $1.4 billion of adjusted free cash flow on a year-to-date basis.
We now expect to invest over $1 billion in acquisitions through the full year.
Accordingly, we are increasing 2021 full year financial guidance as follows: adjusted earnings per share is now expected to be in the range of $4.10 to $4.13; and adjusted free cash flow is now expected to be in the range of $1.475 billion to $1.5 billion.