Counterfeit products may cost the global economy up to $250 billion a year, according to estimates from the Organisation for Economic Co-operation and Development (OECD). Millions of those shipments enter the United States.

While government agencies do their best to crack down on counterfeit goods, they only manage to catch a fraction of the fake products that enter the United States. Still, the U.S. Customs and Border Protection (CBP) values that seized fraction at staggering amounts. The value of counterfeit goods seized rose by 38.1% in 2013, from $1.2 billion in 2012 to $1.7 billion last year.

Based on the manufacturer’s suggested retail price (MSRP) of the genuine versions of the counterfeit goods, some of the most valuable imitations were of handbags and wallets, watches and jewelry, and consumer electronics. 24/7 Wall St. reviewed the nine most counterfeit items seized in 2013, based on their retail value.

The value and number of seizures changes considerably from year to year, depending on what items were being counterfeited, as well as law enforcement activity. Therese Randazzo, director of CBP policy and programs on intellectual property rights, explained that, in some cases, increases in seizures are the result of such activity. In other cases, such as footwear, decreases in seizures can also reflect the success of prior campaigns by CBP and other agencies, she added.

In some cases, changes in the number and value of goods seized did not move in tandem. For instance, while the number of watches and jewelry seized remained roughly the same between 2012 and 2013, the value of those seizures rose by 169%. According to Randazzo, fluctuations will occur with luxury goods like handbags, watches and other types of jewelry in particular, because there is such a large range of values with these products.

Luxury items tend to be the most counterfeited products because they are more valuable, according to Randazzo. And with better counterfeiting methods, there is a greater challenge of detection as well as potential for even higher profits, she explained. Consumers can no longer take for granted obvious signs of imitation such as poor stitching or bad zippers. “Now, the quality [of fake products] has improved so dramatically that [criminals] have been able to charge at prices closer to the price of the genuine article.”

China’s role as manufacturer for a broad range of authentic products, as well as its intellectual property rights framework, may contribute to the country’s high levels of counterfeiting. About $1.2 billion of the $1.7 billion worth of imitations picked up by U.S. law enforcement agencies originated in mainland China. More than $400 million worth of seized goods came from Hong Kong, which CBP classified separately.

The process and methods of detecting these counterfeiting operations is constantly evolving. The increased number of seizures in 2013, according to Randazzo, can be explained in part by new collaborative efforts between CBP and various partners, including China Customs, the customs agency for the People’s Republic of China. The success of such operations has resulted in a measurable increase in the number and value of seizures and the ability to target and intercept shipments of knock-off products, she added.

Based on information provided by the CBP, 24/7 Wall St. reviewed the nine most counterfeited items seized by officials based on the MSRP of the genuine article. We looked at the number of shipments of each product type confiscated in both 2013 and 2012. We also reviewed CBP data by country to identify the value of counterfeit goods produced in specific countries.

These are the nine most counterfeited products in America.