For the years ended December 31, 2024, 2023, and 2022, revenues from sales outside the United States were 48.2%, 63.1%, and 67.6%, respectively, of our total revenues. Net revenues from customers in China and Hong Kong, accounted for approximately 12.6% in 2024, approximately 17.7% in 2023, and approximately 18.8% in 2022 of total net revenues. We expect international sales, notably in Asia, will continue to be a significant component of total sales, since many of the OEMs and ODMs we target as customers are domiciled offshore, and such customers increasingly utilize offshore contract manufacturers, and rely upon those contract manufacturers to place orders directly with us.
To date, we have not experienced material delays or reduced raw material availability as a result of trade disputes between the U.S. and China, including the imposition in 2018 of import tariffs under the provisions of Section 301 of the Trade Act of 1974 (19 U.S.C. § 2411) ("Section 301 Tariffs") on certain Chinese goods imported into the United States. However, the costs of Section 301 Tariffs have had a material impact on our profitability. For the year ended December 31, 2024, Section 301 Tariffs totaled approximately $4,189,000, a decrease of 47.5% compared to $7,985,000 incurred for 2023. For the year ended December 31, 2022, costs associated with tariffs totaled approximately $10,201,000. For 2024, 2023 and 2022, Section 301 Tariffs totaled approximately 1.2%, 2.0% and 2.6%, respectively, of annual revenue, representing a reduction in our gross profit margin as a percentage of annual revenue.
We have filed "duty drawback" applications with U.S. Customs and Border Protection for the recovery of Section 301 Tariffs paid on raw materials and components used to produce products we subsequently exported. We recovered $1,669,000 for the year ended December 31, 2024, however, we are not able to estimate the amount or timing of any additional recoveries, and there can be no assurance that there will be any additional recoveries.
Uncertain macroeconomic conditions, extended trade disputes, an evolving and unpredictable tariff environment, export controls, and the relative strength of the U.S. Dollar may reduce end-demand for our customers' products and, in turn, their purchases of our products, thereby reducing our revenues and earnings. In addition, such adverse conditions may, among other things, result in increased price competition for our products, notably in Brick Product categories, increased risk of excess and obsolete inventories, increased risk in the collectability of our accounts receivable from our customers, increased risk in potential reserves for doubtful accounts and write-offs of accounts receivable, and higher operating costs as a percentage of revenues. We cannot predict the extent and/or impact of the current trade and tariff disputes between the United States and other countries, which adds to the uncertainty and risks associated with our business.