premise: At least 4,272 prisoners were executed in 39 countries last year, while a further 7,017 people were sentenced to death in 76 countries, Amnesty said.
  The figures -- which only represent part of the true number of death sentences and executions -- mark an increase of 30 percent on 1995, when 3,276 prisoners were executed and 4,165 sentenced to death.
  This great leap forward is largely attributed to an anti-crime campaign launched in China last April. Amnesty recorded 3,500 executions in China, most victims being hastily dispatched at the conclusion of dubious trials.
  In Ukraine 169 prisoners were executed, at least 140 in Russia, and more than 110 in Iran.
   What is the cause of most executions in China?
hypothesis: dubious trials