Understandably, there is a lot of interest on the impact of migration and remittances on the Nepalese economy, which receives remittances to the tune of 25% of GDP and was the third largest recipient (% of GDP) in 2011. I see a lot of numbers thrown around to justify various points (including illogical and inconsistent arguments), and I too get a lot of questions on the data and the impact on Nepalese economy.
Below is a chart showing remittances data sourced from Nepal Living Standards Surveys (NLSS). And yes, there are internal remittances as well!
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More on remittances in Nepal here (dig in the archives for information, data and analysis!). A recent Al Jazeera news story here. And, here is a link to a research paper titled 'Remittances in Nepal: Boon or Bane?'.