अशोक के शासनकाल के दौरान, तृतीय बौद्ध संगीति किस वर्ष ईसा पूर्व में आयोजित की गई थी?

In Ancient Indian Statecraft, Kautilya's 'Rajamandala' theory primarily deals with:

The First Buddhist Council was held at ______.

Which ancient Indian text contains references indicating that population counts or census-like records were maintained in ancient India?