According to the 2016 American Express Grow Global Survey, revenues are on the rise for small and mid-sized U.S. companies that sell goods and services internationally.

In the survey of companies selling outside the U.S., 80% say revenues are greater compared to one year ago, and on average, one quarter (26%) of their revenue growth can be linked to international sales alone.

Additionally, as companies forecast future revenues, they are optimistic about exporting. Over the next five years, more than three-quarters (76%) anticipate their revenue from global sales to increase by about 30% on average.

While an overwhelming majority of surveyed companies (90%) agree that international markets offer significant growth opportunities, growth does not come without challenges. The most significant concerns for those selling outside the U.S. include the ability to build relationships with foreign partners (75%) followed closely by the ability to comply with local and international law, trade regulations, and transportation and shipping costs (each, 73%).

Businesses recognize they need help navigating challenges that arise when doing international business, some of which include cultural differences/different business practices (65%), political instability (64%), language barriers (59%) and a general lack of knowledge about the markets in which they operate (57%).

American Express (AXP) created the Grow Global program in 2015 to help ease business owners’ concerns, and provide valuable resources and networking opportunities for U.S. small and medium-sized businesses that currently export as well as those who are considering exporting.

“Our research shows that despite potential challenges, many companies still see international business as an important growth opportunity,” said Ed Marsh, export advisor to American Express. “Through our Grow Global program, we know that getting started can often be the hardest part, but when businesses get on the path to global sales, they realize exporting has organizational benefits beyond just revenue growth.”

According to the survey, most small and mid-size businesses entered foreign markets intentionally as part of a strategic business decision (78%), and many of them (63%) feel informed about how to conduct international business. However, while most intentional exporters feel informed about conducting business globally, almost four in 10 (37%) indicated they have insufficient market knowledge on exporting, meaning they could benefit from the ability to tap into knowledgeable resources. In contrast, as many as one in five small and mid-sized businesses (21%) began exporting accidentally when an opportunity fell into their lap.