With few exceptions, foreign trade in the Comecon countries was a state monopoly, and the state agencies and captive trading companies were often corrupt. Even at best, this tended to put several removes between a producer and any foreign customer, limiting the ability to learn to adjust to foreign customers' needs. Furthermore, there was often strong political pressure to keep the best products for domestic use in each country. From the early 1950s to Comecon's demise in the early 1990s, intra-Comecon trade, except for Soviet petroleum, was in steady decline.