Study says that girl child marriages have significantly declined since 1991.

Childhood marriage, which mostly involves girls, is widely condemned as a violation of individual human rights. Numerous studies have found that child brides are more likely to die young, suffer from serious health problems, live in poverty and remain illiterate.
"There is a global effort to eliminate girl child marriage," said Raj. "Our findings are heartening in terms of eliminating the practice among very young girls, but not among older girls. There needs to be a greater focus on prevention of marriage among later adolescents. If we cannot impact reduction of marriage in this age group, we'll continue to see inadequate change on reduction of girl child marriage as a whole."
Source-Eurekalert