How many signatures are required to start the formal decision making stage of a direct democracy mechanism?

Constitution of Tuvalu

(Adopted on 1 October 1978)

http://www.tuvaluislands.com/const_tuvalu.htm

Article 99, Recall of incapacitated member.

(1) If more than 50percent of the persons who are registered as electors for Parliamentaryelections in an electoral district sign a petition to the Head of State statingthat a member of Parliament for that district is unable to perform properly thefunctions of a member because of infirmity of body or mind, the succeedingprovisions of this section apply.

50% of registered voters in a specific electoral district. However, the recall does not lead to avote of the electorate, but triggers, instead, a discretionary process,overseen by the ‘Head of State’ (the Governor-General) to investigate andapprove the recall of an Minister of Parliament for medical infirmity.