Around 65 percent of Dutch manufacturing exports are self-manufactured. These are the so-called core exports. The remaining 35 percent of exports comprise goods that are not self-manufactured. The bulk of exports that are not self-manufactured concern carry-along trade (CAT). These are export products that are not self-manufactured and that are exported together with the core product to the same destination. Another part of exports is related to the core products, but does not fall under carry-along trade. For example, the export of tobacco which is not produced by a tobacco manufacturer and is destined for a country other than its own tobacco; such exports account for around 9 percent. In addition, there are exports which are not related to the core product and are not CAT exports; this is approximately 7 percent of total manufacturing exports.
In order for exports to classify as CAT, two additional requirements must be met: the combination of core exports and potential CAT exports occurs in at least three reporting years and this combination occupies a share of at least 20 percent in the export combinations of this industry.