memberships. International streaming memberships account for 25% of total streaming memberships at the end of 2013.

The $299.2 million increase in international cost of revenues was primarily due to a $272.0 million increase in content licensing expenses. This increase was primarily attributable to continued investments in existing and new streaming content including content to support the launch of our service in the Nordics (launched in the fourth quarter of 2012) and the Netherlands (launched in the third quarter of 2013). Other costs increased $27.2 million due to increases in our content delivery expenses, costs associated with our customer service call centers and payment processing fees, all driven by our growing member base.

International marketing expenses for the year ended December 31, 2013 increased $10.9 million as compared to the year ended December 31, 2012 due to our expansion in the Nordics and the Netherlands offset partially by a decrease in spending in other territories.

International contribution losses improved $114.8 million year over year, as a result of growing memberships and revenues faster than content and marketing spending. Our International streaming segment does not benefit from the established member base that exists for the Domestic segments. As a result of having to build a member base from zero, investments in streaming content and marketing programs for our International segment are larger initially relative to revenues, in particular as new territories are launched. The contribution losses for our International segment have been significant due to investments in streaming content and marketing programs to drive membership growth and viewing in our international markets.

Domestic DVD Segment

In the Domestic DVD segment, we derive revenues from our DVD-by-mail membership services. The price per plan for DVD-by-mail varies from $4.99 to $43.99 per month according to the plan chosen by the member. DVD-by-mail plans differ by the number of DVDs that a member may have out at any given point. Members electing access to high definition Blu-ray discs in addition to standard definition DVDs pay a surcharge ranging from $2 to $4 per month for our most popular plans.

The $226.1 million decrease in our domestic DVD revenues was due to a 20% decrease in the average number of paid memberships.

The $132.1 million decrease in domestic DVD cost of revenues was primarily due to a $63.2 million decrease in content acquisition expenses and a $47.7 million decrease in content delivery expenses resulting from a 21% decrease in the number of DVDs mailed to paying members. The decrease in shipments was driven by a decline in the number of DVD memberships. Other costs, primarily those associated with content processing and customer service center expenses, decreased $21.2 million primarily due to a decrease in hub operation expenses resulting from the decline in DVD shipments.

Our Domestic DVD segment had a contribution margin of 48% for the year ended December 31, 2013, and was relatively flat as compared to the year ended December 31, 2012.

Prior to July 2011, in the U.S., our streaming and DVDs-by-mail operations were