Gallup analyzed in 2012 how many people who wanted to migrate were in fact actively planning to migrate. It found that among those who say that they want to migrate permanently, 8% plan to do so in the next 12 months and of those 39% were actually preparing to move.
Gallup’s published figures are worldwide, but let’s assume that they apply to specific countries. Take Honduras, where one fifth of the GDP comes from remittances from outside the country, and where per Gallup 47% of adults want to out migrate. (See Gallup here.)
Honduras has about 9 million residents. Thus, about 4.5 million residents (in total families) would be candidates for migration. Of these 39% of 8% of the 4.5 million, 140,000 would be actively arranging to move.
Take the U.S. with a population of 320 million, of which 16% of adults want to migrate. About 10 million would be actively arranging to move.