First, I am pleased to announce that we celebrated a significant milestone during the quarter when we crossed the 1,000 store threshold.
With regards to external growth, we are on pace to achieve record acquisition volume with over $1.7 billion of wholly owned acquisitions, either closed this year or currently under contract and expected to close by year-end.
This represents 115 additional stores and nearly 20% growth in our wholly owned portfolio.
These acquisitions represent a nice mix of both markets and maturity with roughly 1/3 still in lease-up and approximately 75% in the Sunbelt states.
Despite 1/3 in lease-up, we still expect the blended year one cap rate to be in the mid-four range as we remain focused on finding both strategic and FFO accretive opportunities.
Our third-party managed portfolio totaled 357 stores at quarter end and is proving to be the robust acquisition pipeline that we anticipated.
Specifically, 27 stores acquired this year were managed by Life Storage, representing 30% -- 36% of our closed acquisition volume so far this year.
And we continue to onboard additional managed stores at a rapid pace, including 30 in the third quarter alone as owners and developers are attracted to our operating performance and innovative technology platforms.
We have raised the midpoint of our estimated adjusted funds from operations per share to $4.94 this year, which would be a 24% growth over 2020.
We have also nearly doubled the upper end of our acquisition guidance from $1 billion to nearly $2 billion.
Last night, we reported adjusted quarterly funds from operations of $1.37 per share for the third quarter, an increase of 35.6% over the same quarter last year.
Third quarter same-store revenue accelerated significantly again to 17.4% year-over-year, up from 14.7% in the second quarter.
We remain highly occupied with average same-store occupancy up 220 basis points compared to the same quarter last year.
This elevated occupancy has allowed us to continue to be more aggressive with rates on new and existing customers, which has driven a significant increase in our in-place rates per square foot, which were up 14% year-over-year in the third quarter, representing substantial acceleration from the 8% in the second quarter and the 1% in the first quarter.
Same-store operating expenses grew only 3.5% for the quarter versus last year's third quarter.
The increases were partially offset by a 5% decrease in Internet marketing expenses and slightly lower payroll and benefits.
The net effect of the same-store revenue and expense performance was a 390 basis point expansion in net operating income margin to 70.7%, resulting in 24.3% year-over-year growth in same-store NOI for the third quarter.
Additionally, we increased our dividend 16% in October as we continue to share growth in FFO with our shareholders.
This increase follows our 4% dividend bump this past January, and the 7% growth in our dividend last year.
Specifically, we completed an underwritten public offering of common stock, generating approximately $350 million and issued an additional $130 million of common stock via our ATM program.
The company also issued roughly $90 million of preferred operating partnership units as part of the consideration for our portfolio acquisition during the quarter.
Finally, we issued $600 million of 10-year 2.4% senior unsecured notes that priced in late September and closed in early October.
Our net debt to recurring EBITDA ratio was 3.9 times at quarter end and 5.1 times following the completion of the notes offering in October.
Our debt service coverage increased to a healthy 6.3 times at September 30, and we had $500 million available on our line of credit at quarter end.
We have no significant debt maturities until April of 2024 when $175 million becomes due.
And our average debt maturity is 6.3 years.
Specifically, we expect same-store revenues to grow between 12.5% and 13.5%.
Excluding property taxes, we expect other expenses to increase between 1.75% and 2.75% while property taxes are expected to increase 6.75% to 7.75%.
The cumulative effect of these assumptions should result in 17% to 18% growth in same-store NOI.
We have also increased our anticipated acquisitions by $900 million to between $1.7 billion and $1.9 billion.
Based on these assumption changes, we anticipate an adjusted FFO per share for 2021 to be between $4.92 and $4.96.

Summary:
Last night, we reported adjusted quarterly funds from operations of $1.37 per share for the third quarter, an increase of 35.6% over the same quarter last year.