It's also been a strong foundation for how we serve our customers and helped us through the challenges of the last 18 months.
This building is a great asset for Grainger and will continue to ramp capacity through the next 18 months.
Based on our internal scenario planning, we thought that potential adjustments in Q2 would fall somewhere between $45 million and $50 million, while we couldn't predict precisely how far the demand curve would fall or when.
As a result of the sudden weakening of demand, we had more pandemic inventory remaining than expected, and we took a $63 million adjustment, about $15 million more than our internal scenario planning.
We achieved strong organic daily sales growth of 15% for the company on a constant currency basis within our guided range.
When compared to 2019, Q2 was up about 14% on a daily organic basis, a positive indicator of our strong performance and recovery beyond the pandemic.
Our High-Touch Solutions North America segment grew 12.7% on a daily constant currency basis.
Looking at the two-year average in the second quarter of 2021, we drove approximately 275 basis points of average market outgrowth.
We remain very confident in our ability to grow 300 to 400 basis points faster than the market on an ongoing basis.
The Endless Assortment model had another impressive quarter with 23.9% daily sales growth on a constant currency basis, fueled by strong customer acquisition.
Lastly, we generated $269 million in operating cash flow and achieved strong ROIC of 29.2%.
First, our SG&A was $790 million, in line with the guided range provided on our first quarter call.
This resulted in total company operating margin of 10.4%, down 70 basis points compared to the prior year.
Excluding the impact of the $15 million incremental inventory adjustment, GP would have been roughly flat sequentially and operating margin would have been 10.9%.
The resulting earnings per share would have been around $4.50.
We continue to see a robust recovery with daily sales up 13.7% compared to the second quarter of 2020 and up 9.5% compared to the second quarter of 2019.
For the segment, GP finished the quarter at 36.9%, down 125 basis points versus the prior year.
I think it's important to note that without the $63 million of inventory adjustment, GP would have been up 125 basis points year-over-year.
This 250 basis point swing demonstrates that our underlying GP rate would have otherwise been a healthy 39.4%.
SG&A in the segment ramped as expected to $640 million, lapping the lowest point of SG&A spend in the second quarter of 2020.
Canada continued to make solid progress and expanded operating margin approximately 315 basis points year-over-year.
Accordingly, pandemic sales declined approximately 28% versus 2020.
However, that's an impressive 27% increase versus 2019.
We estimate July 2021 will be down about 28% over July 2020, in line with what we saw in the second quarter of this year.
During the quarter, we grew 31% versus 2020 and up 7% versus 2019.
We estimate that for the month of July 2021, non-pandemic sales growth of about 22%.
As it relates to pandemic product mix, while we expected it to taper off to near pre-pandemic levels to about 20% by year-end, we're seeing this happen more quickly now at about 22% of sales.
In total, our U.S. High-Touch Solutions business is up about 12% for the second quarter of 2021 and up 10% over 2019.
At this time, the market declined between 14% and 15% and we saw outsized share gains of roughly 1,200 basis points.
MRO market grew between 18.5% and 19.5%.
The U.S. High-Touch business grew 12.4%, about 650 basis points lower than the market.
To normalize for the volatility, we calculated the two-year average share gain to be 275 basis points over the market.
As I previously noted, our U.S. High-Touch business is up 10% over 2019.
As previously discussed, our second quarter GP decline resulted from the $63 million inventory adjustment.
This adjustment lowered U.S. GP by 270 basis points.
Without this, our underlying U.S. GP rate is 39.8% in the second quarter.
We're doing everything within our control to exit the year with a Q4 GP rate at or above the Q1 2020 levels or 40.1%.
Daily sales increased 23% or 23.9% on a constant currency basis, driven by continued strength in new customer acquisitions at both Zoro and MonotaRO as well as growth of larger enterprise customers in MonotaRO.
GP expanded 75 basis points year-over-year driven by positive trends at both businesses, and operating margin finished up 95 basis points over the prior year.
In local currency and using Japan's local selling days, which occasionally differ from U.S. selling days, MonotaRO's daily sales grew 16.7% with GP finishing the quarter at 26.4%, 25 basis points above the prior year.
Operating margin decreased 15 basis points to 12% as they continue to ramp up operations at the Ibaraki DC.
Switching to Zoro U.S., daily sales grew 32.6% as it laps its softest quarter of 2020.
Zoro GP grew 95 basis points to 31.5% and achieved 320 basis points of operating margin expansion through substantial SG&A leverage in the quarter.
Both MonotaRO and Zoro have shown progress and are up over 20% over the second quarter last year.
At the end of the second quarter of 2021, we had a total of 7.5 million SKUs available online, close to our goal of eight million for the year.
For the third quarter, on a total company level, we expect our revenue growth to be between 10% and 11% on a daily organic basis.
We believe any material pandemic-related inventory adjustments are complete, and we expect GP to be up between 100 and 120 basis points year-over-year and to improve sequentially.
SG&A is anticipated to fall between $805 million and $815 million as we continue to invest in marketing and wages in the DCs to remain competitive.
We just set a new goal last year to reduce the absolute Scope one and two greenhouse gas emissions by 30% by 2030.
We now offer more than 100,000 environmentally friendly products.

Summary:
Our High-Touch Solutions North America segment grew 12.7% on a daily constant currency basis.