Occupancy increased further in March, ending the quarter with the year-over-year positive delta of 480 basis points.
Our elevated occupancy has given us significant pricing power, which has also accelerated during the quarter with achieved rates increasing from 10% in January to well into the teens by the end of March.
These trends fueled same-store revenue growth of 4.6% despite a 110 basis point drag on revenue growth from lower year-over-year late fees.
We had excellent expense control with 0.2% decrease in same-store expenses.
The result with same-store NOI growth of 6.5% a sequential acceleration of 310 basis points from Q4 and year-over-year core FFO growth of 21%.
Year-to-date, we've been able to close or put under contract a little over $300 million in acquisitions.
We were very active in Q1 on the third-party management front, adding 61 stores in the quarter, which includes the previously announced JCAP stores.
Our first quarter outperformance coupled with steady external growth and the improving 2021 outlook allow us to increase our industry-leading annual guidance $7.5 at the midpoint.
We delivered a reduction in same store expenses despite property tax increases of 6.9% and repairs and maintenance increases of 20% due to higher year-over-year snow removal costs.
Core FFO for the quarter was $1.50 per share, a year-over-year increase of 21%.
We continued to strengthen our balance sheet during the quarter through ATM activity and an overnight offering, which combined for net proceeds of $274 million.
We sold 16 stores into a joint venture and obtained debt for that venture, resulting in cash proceeds to Extra Space of $132 million and an ownership interest of 55%.
We plan to add a third partner to this venture in the second quarter, which will reduce our ownership interest to 16%.
Our equity and disposition proceeds reduced revolving balances and we ended the quarter with net debt to EBITDA of 5.1 times lower than our long-term debt target of 5.5 times to 6 times.
We raised our same-store revenue range to 5% to 6%.
Same-store expense growth was reduced to 2% to 3%, resulting in same-store NOI growth range of 6% to 8%, a 175 basis point increase at the midpoint.
We raised our full year core FFO range to be $5.95 to $6.10 per share, a $7.5 increase at the midpoint.
We anticipate $0.14 of dilution from value-add acquisitions in C of O stores, $0.02 less than previously reported due to improved property performance.

Summary:
Core FFO for the quarter was $1.50 per share, a year-over-year increase of 21%.
We raised our full year core FFO range to be $5.95 to $6.10 per share, a $7.5 increase at the midpoint.