LANDSTAR SYSTEM/ 2
contribution also reached an all-time quarterly record of $242.3 million in the 2021 third quarter compared to $160.9 million in the 2020 third quarter. A tabulation of the expenses identified as costs of revenue as well as a reconciliation of gross profit to variable contribution and gross profit margin to variable contribution margin for the 2021 and 2020 third quarters and year-to-date periods is provided in the Company’s accompanying financial disclosures.
Trailing twelve-month return on average shareholders’ equity was 43 percent and return on invested capital, representing net income divided by the sum of average equity plus average debt, was 38 percent. During the 2021 third quarter, Landstar purchased 167,000 shares of its common stock bringing the year-to-date number of shares purchased to 317,000 at an aggregate cost of $50 million. The Company is currently authorized to purchase up to approximately 1,504,000 additional shares of the Company’s common stock under its previously announced share purchase program. Landstar announced today that its Board of Directors has declared a quarterly dividend of $0.25 per share payable on December 3, 2021, to stockholders of record as of the close of business on November 9, 2021. It is currently the intention of the Board to pay dividends on a quarterly basis going forward.
Truck transportation revenue hauled by independent business capacity owners (“BCOs”) and truck brokerage carriers in the 2021 third quarter was $1.581 billion, or 91 percent of revenue, compared to $1.006 billion, or 93 percent of revenue, in the 2020 third quarter. Revenue hauled by rail, air and ocean cargo carriers was $128.6 million, or 7 percent of revenue, in the 2021 third quarter compared to approximately $62 million, or 6 percent of revenue, in the 2020 third quarter.
The supplemental information schedule included as a table to this press release includes changes to the historical classification of truck services and equipment type. Power-only, expedited, straight truck, cargo van and miscellaneous other truck transportation services that were formerly included in revenue from van or unsided/platform services have been classified in a single line item named “other truck transportation” as demand for these types of truck services increased significantly during the pandemic. Other truck transportation revenue was 13.2 percent and 10.8 percent of total truck transportation revenue in the 2021 and 2020 third quarters, respectively.