adversely affect the collectability of our receivables. If the availability of credit to our customers is reduced, they may reduce their drilling and production expenditures, thereby decreasing demand for our products and services, which could have a negative impact on our financial position. Additionally, unsettled conditions could have an impact on our suppliers, causing them to be unable to meet their obligations to us. Although we do not currently anticipate a need to access the credit markets in the short term, a prolonged constriction on future lending by banks or investors could result in higher interest rates on future debt obligations or could restrict our ability to obtain sufficient financing to meet our long-term operational and capital needs. The revenues projected in our backlog may not be realized or, if realized, may not result in profits. All of the projects currently included in our backlog are subject to change and/or termination at the option of the customer. In the case of a change or termination, the customer is generally required to pay us for work performed and other costs necessarily incurred as a result of the change or termination. We can give no assurance that our backlog will remain at current levels. Sales of our products are affected by prices for oil and natural gas, which have fluctuated significantly and may continue to do so in the future. When drilling and production levels are depressed, a customer may no longer need the equipment or services currently under contract or may be able to obtain comparable equipment or services at lower prices. As a result, customers may exercise their termination rights or attempt to renegotiate contract terms. Continued declines in oil and natural gas prices could also reduce new customer orders, possibly causing a decline in our future backlog. If we experience significant project terminations, suspensions or scope adjustments to contracts reflected in our backlog, our financial condition, results of operations and cash flows may be adversely impacted. We have substantial international operations, with approximately 63%, 67% and 74% of our revenues derived from foreign sales in 2014, 2013 and 2012, respectively. We operate our business and market our products and services in many of the significant oil and gas producing areas in the world and are, therefore, subject to the risks customarily attendant to international operations and investments in foreign countries. Risks associated with our international operations include: Our international operations expose us to instability and changes in economic and political conditions and other risks inherent to international business, which could have a material adverse effect on our results of operations, financial position or cash flows. Our backlog is subject to unexpected adjustments and cancellations and is, therefore, an uncertain indicator of our future revenues and earnings. • volatility in general economic, social and political conditions; • terrorist threats or acts, war and civil disturbances; • expropriation or nationalization of assets; • renegotiation or nullification of existing contracts; • foreign taxation, including changes in laws or interpretations of existing laws; • assaults on property or personnel; • restrictive action by local governments; • foreign and domestic monetary policies; • limitations on repatriation of earnings; • travel limitations or operational problems caused by public health threats; and • changes in currency exchange rates. Any of these risks could have an adverse effect on our ability to manufacture products abroad or the demand for our products and services in some locations. To date, we have not experienced any significant problems in 18