Now at Carnival Cruise Line, we were able to offer more comparable itineraries than 2019, our revenue per dims were up 20% compared to 2019 and that's inclusive of the impact of incentives from previous cancellations, and that's despite the quoting nature of the bookings.
In fact, Carnival Cruise Lines restarted more ships out of the United States than any of the cruise brand and still achieved occupancy above 70%, all of which combined to generate an even greater cash contribution.
Of course, agility has been a key strength of ours over the last 18 months, and we continue to aggressively manage to optimize given this ever-changing landscape.
In fact, while by design, we're not yet at 100% occupancy.
We have individual sailings with over 4,000 guests.
To-date, we have carried over 0.5 million guests this year already.
And on any given day, we are now successfully carrying around 50,000 guests, and expect that number to continue to rise as we introduce more capacity and as we increase occupancy over the coming months.
So far, we've announced the resumption of guest cruise operations for 71 ships through next spring, and that's across eight of our nine brands.
We're evaluating the remaining shifts through next spring, with a continued focus on maximizing future cash flow while delivering a great guest experience in a way that serves the best interest of public health.
We have also opened bookings earlier for cruises in 2023, and we're achieving those early bookings with strong demand and good prices.
In fact, these efforts contributed to the $630 million increase in guest deposits, our long-term guest deposits.
And that's deposits on bookings beyond 12 months, are 3 times historical levels, driven in part by our proactive efforts to open more inventory for sale in outer years.
We continue to focus our efforts on our lower cost channels like direct marketing to our sizable past guest database of over 40 million guests, and earned media, as we build on our multiple new ship launches and restart news flow.
In the report, we build on the achievement of our 2020 goal by sharing more details on our 2030 goals and our 2050 aspiration.
We are committed to decarbonization, and we aspire to be carbon neutral by 2050.
As we have previously shared, despite 25% capacity growth since that time, our absolute carbon emissions peaked in 2011 and will remain below those levels.
I'm very humbled by the dedication I've seen in these past 18 months.
Our strategic decision to accelerate the exit of 19 ships left us with a more efficient and effective fleet, and has lowered our capacity growth to roughly 2.5% compounded annually from 2019 through 2025, and that's down from 4.5% pre-COVID.
And we will achieve a structural benefit to unit costs in 2023 as we introduce these new, larger and more efficient ships, coupled with the 19 ships leaving the fleet, which were among our least efficient, with the aggressive actions we've already taken, optimizing our portfolio and reducing capacity.
I'll start today with a review of our guest cruise operations along with our third quarter monthly average cash burn rate.
We ended the quarter with 35% of our fleet capacity in service.
Our plans call for another 27 ships to restart guest cruise operations during the fourth quarter and the month of December.
So on New Year's Day, we anticipate celebrating with 55 ships or nearly 65% of our fleet capacity back in service.
For the third quarter, occupancy was 54% across the ships in service.
Occupancy did improve month-to-month through the quarter and in the month of August, occupancy reached 59% from 39% in June and 51% in July.
Occupancy for our North American brands reflects our approach of vaccinated cruises, which for the time being, does limit the number of families with children under 12 that can sail with us.
Occupancy for our European brands reflects capacity restrictions, such as social distancing requirements for our Continental European brands and a 1,000-person cap per sailing for some of the quarter in the U.K. For the full third quarter, our North American brands occupancy was 68%, while for our European brands, occupancy was 47%.
Revenue per passenger cruise day for the third quarter 2021 increased compared to a strong 2019 despite the current constraints on itinerary offerings which did not include many of the higher-yielding destination-rich itineraries offered in 2019.
As we previously guided, the ships in service during the third quarter were, in fact, cash flow positive.
They generated nearly $90 million of ship level cash contribution.
For those of you who are modeling our future results, I did want to point out that due to the cost of a portion of our fleet being in pause status during the first half of 2022, restart related expenses and the cost of maintaining enhanced health and safety protocols, we are projecting ship operating expenses in 2022 per available lower berth day or per ALBD, as it is more commonly called, to be higher than 2019 despite the benefit we get from the 19 smaller, less efficient ships leaving the fleet.
We do anticipate that most of these costs and expenses will end with 2022 and will not reoccur in fiscal 2023.
For the third quarter 2021, our cash burn rate was $510 million per month, which was better than our previous guidance and was in line with the $500 million per month for the first half of 2021.
With the timing of certain capital expenditures now shifting to the fourth quarter, the company expects its monthly average cash burn rate for the fourth quarter to be higher than the monthly average rate for the first nine months of the year.
Other good news positive factors impacting the fourth quarter are restart expenditures to support not only the 22 ships that will restart during the fourth quarter but also the additional ships that will restart in the first quarter of 2022, along with the significant increase in dry dock days during the fourth quarter, driven by the restart schedule.
Also, during the fourth quarter, we are forecasting positive cash flow from the 50 ships that will have guest cruise operations during the quarter.
And ALBDs for the fourth quarter are expected to be 10.3 million, which is approximately 47% of our total fleet capacity.
Our booking volumes for the all future cruises during the third quarter 2021 were higher than booking volumes during the first quarter.
Our cumulative advanced book position for the second half of 2022 is ahead of a very strong 2019 and is at a new historical high.
To-date, through our debt management efforts, we have reduced our future annual interest expense by over $250 million per year.
And we have completed cumulative debt principal payment extensions of approximately $4 billion, improving our future liquidity position.
The $4 billion extension results from three things: first, the July refinancing of 50% of our first lien notes were $2 billion.
Second, the completion of the European debt holiday amendments, which deferred $1.7 billion of principal payments.
And third, the extension of a $300 million bilateral loan with one of our banking partners.

Summary:
We're evaluating the remaining shifts through next spring, with a continued focus on maximizing future cash flow while delivering a great guest experience in a way that serves the best interest of public health.
We have also opened bookings earlier for cruises in 2023, and we're achieving those early bookings with strong demand and good prices.
I'll start today with a review of our guest cruise operations along with our third quarter monthly average cash burn rate.
Revenue per passenger cruise day for the third quarter 2021 increased compared to a strong 2019 despite the current constraints on itinerary offerings which did not include many of the higher-yielding destination-rich itineraries offered in 2019.
As we previously guided, the ships in service during the third quarter were, in fact, cash flow positive.
We do anticipate that most of these costs and expenses will end with 2022 and will not reoccur in fiscal 2023.
For the third quarter 2021, our cash burn rate was $510 million per month, which was better than our previous guidance and was in line with the $500 million per month for the first half of 2021.
With the timing of certain capital expenditures now shifting to the fourth quarter, the company expects its monthly average cash burn rate for the fourth quarter to be higher than the monthly average rate for the first nine months of the year.
Our booking volumes for the all future cruises during the third quarter 2021 were higher than booking volumes during the first quarter.
Our cumulative advanced book position for the second half of 2022 is ahead of a very strong 2019 and is at a new historical high.