The flood of allegations, lawsuits and official reports into clerical abuse reached a peak in 2009 and 2010, which observers say may explain the spike shown in the document.
The Holy See is a signatory to the UN Convention on the Rights of the Child, a legally binding instrument which commits it to protecting and nurturing the most vulnerable in society.
It ratified the convention in 1990 but after an implementation report in 1994 it did not submit any progress reports until 2012, following revelations of child sex abuse in Europe and beyond.
Last month, the Vatican refused a request from the UN's Committee on the Rights of the Child for data on abuse, on the grounds that it only released such information if requested to do so by another country as part of legal proceedings.
In a homily on Thursday, Benedict's successor, Pope Francis, called abuse scandals "the shame of the Church".
He announced in December that a Vatican committee would be set up to fight sexual abuse of children in the Church.