Um artigo excelente que eu achei nessa revista (Would You Ask Turkeys to Mandate Thanksgiving? The Dismal Politics of Legislative Transparency) menciona o seguinte fato a respeito do congresso americano:
that is, they are not attributed to individual legislators.
Instead, they are only tallied in the
aggregate, either with precise counts or by
voice vote, noting that a measure did or did not
pass (Oleszek, 2006). For example, a large fraction
of bills passed out of Congressional committees
to the floor are by voice vote. During
the first week of May 2008 (May 1 to 7), Congressional
committees passed 22 bills. Of those,
18 were by voice vote, three by roll call vote,
and one (the defense authorization bill for
FY2009) in closed session.
(roll call votes são votações em que o voto é guardado pra cada deputado, as opposed to voice votes onde não fica registro)