Rent collections, for example, during April and May were 35%, that grew to 80% in the third quarter.
And as of today, the fourth-quarter rent collections were at 92% and rising by the week.
Currently, 10% of the U.S. population has had at least one dose of the vaccine, and distribution is accelerating.
In fact, December sales were approaching 85% of pre-COVID levels even in the midst of a surge in COVID cases.
The result is our occupancy level is at 90%, which is the lowest since the Great Financial Crisis.
Of our 27 JCPenney locations, only two locations closed, Green Acres and Kings Plaza, both in New York.
Rent collections have improved significantly, up from a September collection rate of 77%, and are now above 90% in the fourth quarter.
January is also trending above 90%.
We have come to agreement on COVID workouts with over 93% of our top 200 tenants.
Volumes, in fact, were 90% of pre-COVID levels of the fourth quarter of 2019.
Our 2021 lease expirations are 60% leased today, with the majority of the balance in the letter of intent stage.
Retailer traffic and sales continue to pick up with traffic at 80% of pre-COVID traffic and sales, on average, 85% of pre-COVID levels.
1 Global Real Estate Sustainability Benchmark Ranking in the North American retail sector.
Funds from operations for the fourth quarter was $0.45.
That's down from the fourth quarter of 2019 at $0.98 per share.
Same-center net operating income for the quarter was down 33%, and year to date is down 22%.
One, $38 million decline from COVID-related rent abatements across permanent and temporary leasing revenue line items.
Fourth-quarter abatements were elevated relative to the third-quarter abatements of $28 million, and this was largely due to the protracted summer closures of several large properties in New York and in California.
Cumulatively for the year, in 2020, we granted $56 million of abatements.
Number two, $19 million of COVID-related decline in common area and ancillary revenues, including specialty leasing and temporary tenant revenue, percentage rent revenue, business development revenue, and parking revenue.
In total, for all of 2020, these line items were down $43 million.
Number three, general top-line revenue decrease is totaling approximately $12 million, driven primarily by COVID-related occupancy decreases.
Number four, $6 million of bad debt expense in the form of reversals of lease revenue for tenants on a cash basis pursuant to GAAP, that was about $5 million, and then bad debt expenses of about $1 million.
As a result of the COVID-related disruption to our business, the bad debt expense line item was significantly elevated in 2020 at $62 million.
This was a $52 million increase versus $10 million of bad debt expense in 2019.
Number five, there was an $8 million decrease from loss or gain on un-depreciated asset sales or writedowns on consolidated assets.
This included a $5 million impairment charge in the fourth quarter of 2020 for undeveloped land that is currently under contract for sale and is expected to close in 2021.
And lastly, offsetting these items, straight-line rent increased $19 million in the fourth quarter.
So to summarize some of the major impacts of COVID that impacted real estate NOI in 2020, and again, all these figures are at the company's share, we highlight the following: number one, $56 million of one-time retroactive abatements of rent.
Number two, a $43 million of decline in common area and ancillary revenues, percentage rent and temporary -- or excuse me, and parking revenues.
And number three, we wrote-off an extra $52 million of bad debt expense relative to 2019.
Plus, in addition, we had another $11 million of rent that was reversed for tenants that are accounted for on a cash basis.
So when you add all that up, collectively, it's roughly $162 million of pandemic-driven NOI decline just among those three categories.
2021 FFO is estimated in the range of $2.05 per share to $2.25 per share.
In terms of FFO by quarter, we estimate the following cadence: 21% in the first quarter, 24% in 2Q, 25% in 3Q, and the balance 30% in the last quarter.
Trough occupancy appears to have been contained to roughly 88%, which we estimate to be at the end of the first quarter.
As addressed in detail within our recent filings, over the last few months, we have successfully extended four secured mortgage loans, totaling over $660 million for extension terms ranging up to three years.
The loan is a $95 million mortgage loan, bearing fixed interest at 3.3% for 10 years.
At closing, this generated $45 million of incremental liquidity to the company, and there is some incremental funding capacity remaining under this line item.
Cash on hand at year-end was $555 million.
As Tom previously noted, collection efforts are now over 90%.
And in addition, we estimate the collections of both contractually deferred and delayed rent collections in 2021 that relate to 2020 billed rents in the approximate range of $60 million to $75 million.
During 2021, we expect to generate over $200 million of cash flow from operations, and this is after recurring operating and leasing capital expenditures and after dividend.
And as for development, we expect to spend less than $100 million in 2021, excluding further development expenditures on One Westside, which recall, is independently funded by a construction loan facility.
Looking at our top 200 rent-paying national retailers, we now have commitments with 176, which is up considerably from last quarter.
But more importantly, we now have received payments, or we've worked out deals totaling 93% of the total rent these top 200 pay.
As of today, collection rates increased to 89% in the third quarter and 92% in the fourth quarter of 2020.
Occupancy at the end of the third quarter was 89.7%, that's down 110 basis points from last quarter and down 4.3% from a year ago.
Temporary occupancy was 5.9%, and that's down 50 basis points from this time last year.
Trailing 12-month leasing spreads were a negative 3.6%, and that's down from 4.9% last quarter and down from 4.7% in 2019.
Average rent for the portfolio was $61.87 as of December 31, 2020, and this represents a 1.3% increase compared to $61.06 as of December 31, 2019, and a 0.7% decrease compared to $62.29 at September 30, 2020.
And to date, we have commitments on 60% of our expiring square footage, with another 40%, or the balance, in the letter of intent stage, disregarding tenants who have closed or have indicated they intend to close.
In the fourth quarter, we signed 217 leases for 900,000 square feet.
This represents 80% more leases and 1.5 times the square footage when compared to the third quarter of 2020.
This also represents 90% of the square footage that we signed in the fourth quarter of 2019.
We opened 59 new tenants in 236,000 square feet, resulting in a total annual rent of over $10 million.
In the large-format category, we opened DICK's Sporting Goods at Vintage and Round 1 at Deptford Mall, both in former Sears locations.
We already have signed leases totaling approximately 494,000 square feet, all scheduled to open in 2021, and this list continues to grow.
Later this year, we look forward to opening an amazing two-level, 11,000-square-foot flagship Dior store at Scottsdale Fashion Square, the first and only Dior in all of Arizona.
Primark is well under construction and will open its highly anticipated 50,000 square foot store at Fashion District Philadelphia in September of this year.
And when we look at deals still in lease negotiation, we have yet another 435,000 square feet to open in 2021, and this number grows daily.

Summary:
Funds from operations for the fourth quarter was $0.45.
2021 FFO is estimated in the range of $2.05 per share to $2.25 per share.
Occupancy at the end of the third quarter was 89.7%, that's down 110 basis points from last quarter and down 4.3% from a year ago.