As we sit here today, over 50% of adults in the U.S. have at least one vaccine shot and at the current pace there is potential for 90% of adults in the U.S. to be vaccinated by summer.
Our tenants are open and operating, our collections continue to be sector leading, up to 97% this quarter and the velocity of demand for our well-located centers is accelerating.
We had another very strong quarter of leasing, signing over 426,000 square feet of space at blended lease spreads of 12.2% and 6.4% on a GAAP basis and cash basis respectively.
Excluding a single strategic anchor renewal, we realized blended leasing spreads of 16.7% and 10.5% on a GAAP and cash basis respectively.
Our current signed, not open NOI is approximately $10 million, which will come online in late 2021 and early 2022.
Speaking of Raleigh, as I'm sure you've all heard earlier in the week, Apple announced the creation of a $1 billion East Coast campus in the Research Triangle Park located in the Raleigh, Durham MSA.
KRG will be a direct beneficiary of this announcement as we own Parkside Town Commons, a 350,000 square foot Target in Harris Teeter anchored center that is adjacent to the future campus.
Assuming an average salary of $187,000, the 3,000 new employees will generate over $550 million of annual spending power.
78% of our ABR is located in the South and West.
Our next closest peer has less than 50% of their ABR in those same markets.
As we discussed on our fourth quarter call, we partially match funded our Eastgate acquisition by selling 17 ground leases for a combined $41.8 million.
On the anchor front, we've already executed four leases and are negotiating multiple leases on the remaining 23 vacant boxes.
As we discussed last quarter, assuming the current ABR for our in-place anchors, there is a potential mark to market of nearly 20%.
To increase transparency, we've added Page 22 in the sup so you can track our progress as we lease up boxes.
The four leases signed to date have achieved a 12% lease spread and over a 40% return on capital.
As shown on Page 4, we have the potential to increase our NOI by roughly 14% simply by leasing up vacant space to pre-COVID levels at current portfolio ABR.
Turning to our first quarter results, we generated $0.34 of NAREIT FFO and we also generated $0.34 of FFO as adjusted.
As set forth on Page 17 of our supplemental, the net 2020 collection impact in the first quarter was de minimis with the collection of $2.2 million of prior bad debt, offset by $1.9 million of accounts receivable we've now deemed to be on the collectables.
There are other several notable items on Page 17 of the supplemental that demonstrate our improving fundamentals on a sequential basis.
Total bad debt to this quarter was $1.6 million as compared to $2.6 million for the fourth quarter of 2020.
As for accounts receivable, we collected $5.8 million that was outstanding at year end, including deferred rents.
Today, total outstanding deferred rent stands at $3.5 million, down from $6.1 million at year end, with only $30,000 delinquent to date.
With respect to our small business loan program, the total balance is down to $1.4 million and not a single tenant is delinquent.
Our same-store NOI growth this quarter is negative 2.9% as a result of COVID-related vacancies.
This includes the benefit of approximately $800,000 of previously written-off debt that we collected in the first quarter.
Excluding those amounts, our same-store NOI would be negative 4.5%.
At 160 basis point difference, it's just noise from 2020 and is precisely why we didn't provide guidance on this metric.
Our net debt to EBITDA, pro forma for the ground lease dispositions, was 6.6 times, down from 6.8 times last quarter.
During the first quarter, we issued $175 million of exchangeable notes due in 2027.
These notes have an interest coupon of 0.75%.
In conjunction with these notes offerings, we entered into a capped call transaction to increase the conversion price of the notes to $30.26.
Excluding future lease-up costs, we have only $15 million of outstanding capital commitments and have roughly $420 million of liquidity.
We are raising our 2021 guidance of FFO as adjusted to be between $1.26 and $1.34 per share.
This guidance assumes full year bad debt of approximately $7.6 million and no additional material transactional activity.

Summary:
Turning to our first quarter results, we generated $0.34 of NAREIT FFO and we also generated $0.34 of FFO as adjusted.
We are raising our 2021 guidance of FFO as adjusted to be between $1.26 and $1.34 per share.