A lack of access to Cuba,says GAO, has made it difficult to obtain nationally representative data on audience size, and decision-makers have had limited information to assess the relative success or return on investment for each transmission method.
VOA: standard.2009.06.18
Tax returndata is unsuited for measuring income distribution for other reasons as well.
Long term market risk and returndata may start as an initial guide for this process, further augmented by an understanding of the current market environment.
That and the growth of the other businesses now reporting as individuals has made the top income shares measured by tax returndata continue to appear to rise more rapidly since then.