Among other accomplishments, we celebrated the addition of store #2000 to our portfolio.
Same-store occupancy once again reached a new all-time high during the quarter at over 97%, with vacates continuing at lower-than-historic levels.
Achieved rates to new customers in the quarter were 43% higher than 2020 levels and 41% greater than 2019 levels.
Other income improved significantly year-over-year, primarily due to increased late fees contributing 30 basis points to revenue growth in the quarter.
These drivers produced same-store revenue growth of 18.4%, a 480 basis point acceleration from Q2.
And same-store NOI growth of 27.8%, an acceleration of 760 basis points.
In addition, our external growth initiatives produced steady returns outside of the same-store pool, resulting in FFO growth of 41.2%.
While most of our transactions have been in relatively small bites, the total is adding up, allowing us to increase our investment guidance to $700 million for the year.
We had an incredibly strong quarter on the third-party management front, adding 96 stores.
In the quarter, we purchased 11 of our managed stores in the REIT or in a joint venture for a total of 30 stores purchased from our third-party platform through September.
Fundamentals have remained even stronger than our already positive outlook, allowing us to raise our annual FFO guidance by $0.28 at the midpoint.
While we still assume a seasonal occupancy moderation, it has been less than our initial estimate of 300 basis points from this summer's peak.
Our revised guidance now assumes a 200 basis point moderation which would result in 2021 year-end occupancy generally similar to that of 2020.
Core FFO for the quarter was $1.85 per share, a year-over-year increase of 41.2%.
As a result of our strong FFO growth, our Board of Directors raised our third quarter dividend an additional 25% after already raising it 11% earlier this year, a total increase of 38.9% over the third quarter 2020 dividend.
We delivered a reduction in same-store expenses in the quarter, including a 3% savings in payroll, 42% savings in marketing and a 4% decrease in property taxes due to some successful appeals.
And we completed a successful second offering in the third quarter, issuing another $600 million 10-year bond at a rate of 2.35%.
We also refiled our ATM in the quarter, and we have $800 million in availability.
Our quarter end net debt to EBITDA was 4.5 times, giving us significant dry powder for investment opportunities while maintaining our credit ratings.
We raised our same-store revenue range to 12.5% to 13.5%.
Same-store expense growth was reduced to negative 1% to 0%, resulting in same-store NOI growth range of 18% to 19.5%.
We raised our full year core FFO range to be $6.75 to $6.85 per share.
Due to stronger lease-up performance, we dropped our anticipated dilution from value-add acquisitions and C of O stores from $0.12 to $0.11, even after adding a number of additional lease-up properties to our acquisition pipeline.

Summary:
These drivers produced same-store revenue growth of 18.4%, a 480 basis point acceleration from Q2.
Core FFO for the quarter was $1.85 per share, a year-over-year increase of 41.2%.
We raised our full year core FFO range to be $6.75 to $6.85 per share.