For the fourth quarter, we achieved record net sales of about $4.2 billion and our adjusted earnings per diluted share from continuing operations for $1.26.
Excluding the favorable impact from the tax rate, our adjusted earnings per share was about 10% below the financial guidance we've provided in October.
Our PPG-Comex business delivered yet again another excellent quarter and finished with 10% organic sales growth for the full year of 2021.
And in January, we will have 5,000 concessionaire locations in our network.
Recently, some of our manufacturing facilities have had up to 40% of their workforce out.
Overall, our sales backlog grew, and in total, was about $150 million exiting the quarter, most notably in our aerospace and automotive refinish and general industrial businesses.
Raw material cost inflation was up approximately 30% compared to prior year.
These increased operating costs impacted the quarter by $0.20 per share, and COVID-related absenteeism has continued in January.
In aggregate, our selling price realization in the fourth quarter was about 8%, with a higher price realization in our industrial reporting segment.
Reflecting back to 2021, we achieved all-time record sales of $16.8 billion led by strategic acquisitions and strong organic growth of 10% despite the various ongoing supply chain challenges we incurred.
In addition, we delivered record earnings per share growth of more than 10% even with raw material cost inflation of about 20% for the full year, the highest level of coatings industry inflation in recent memory.
We, once again, lowered our SG&A as a percentage of sales, decreasing by about 200 basis points, aided by delivering $135 million in restructuring savings in 2021.
We also advanced our digital capabilities in many businesses, most notably the architectural coatings business or sales transaction on a digital platform increased by 20% compared to 2020, as we see our customers' digital patterns become more ingrained.
We're among a small number of companies that have achieved this milestone, along with even fewer companies paying a dividend for more than 120 consecutive years.
Finally, we have lowered our net debt by about $350 million since funding Tikkurila in June and exited 2021 with a strong balance sheet and optionality for future accretive cash deployment.
Tightened supply and COVID-related disruptions evidenced in the fourth quarter are expected to continue into the first quarter of 2022 impacting our ability to manufacture and deliver product.
We plan to implement further selling price increases in all our businesses as raw materials and other cost inflation remain at elevated levels and are increasing further in certain areas.
This includes: first, continued recovery in the automotive refinish, OEM, and aerospace coatings businesses, which collectively account for about 40% of our pre-pandemic sales and where we have broad global businesses supported by advantaged technologies.
The volume for these businesses remain about 15% below pre-pandemic levels.
And we are already experiencing improving order flow that is being crimped by supply availability; second, normalization of commodity raw material costs, which should moderate over time as supply dislocations improve; third, higher operating leverage on sales volumes supported by our lower cost structure; fourth, year-over-year earnings growth in 2022 and 2023 due to further synergy capture from our recent acquisitions, including a 15% increase to our original synergy target; and finally, above market organic growth driven by our advantaged and leading brands, technology, and services.
This initiative strongly supports our asset-light strategy by adding more than 2,000 distribution locations.
Together with The Home Depot, we are positioned to outgrow the pro market in the U.S. Considering all of these catalysts, I believe we have a path to at least $9 of earnings per share in 2023.

Summary:
For the fourth quarter, we achieved record net sales of about $4.2 billion and our adjusted earnings per diluted share from continuing operations for $1.26.
Excluding the favorable impact from the tax rate, our adjusted earnings per share was about 10% below the financial guidance we've provided in October.
Overall, our sales backlog grew, and in total, was about $150 million exiting the quarter, most notably in our aerospace and automotive refinish and general industrial businesses.
Raw material cost inflation was up approximately 30% compared to prior year.
Tightened supply and COVID-related disruptions evidenced in the fourth quarter are expected to continue into the first quarter of 2022 impacting our ability to manufacture and deliver product.
We plan to implement further selling price increases in all our businesses as raw materials and other cost inflation remain at elevated levels and are increasing further in certain areas.