The latest estimates of the Planning Commission states the decline in the number of poor in Sikkim from 1,70,000 to 51,000 in the seven year period between 2004-05 to 2011-12.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/poverty-declines
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/statesman-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/sikkim
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/poverty
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/planning-commission