Psalms 67 (NWT)
11 Jehovah himself gives the saying;
The women telling the good news are a large army.
12 Even the kings of armies flee, they flee.
As for her who abides at home, she shares in the spoil.
This scripture is taken from King David's time, not Jesus' time. Especially during times of warfare, the female population was larger than the male population due to wartime deaths. We can see a similar trend during World War II: "As with most wars, many women found their roles and opportunities -- and responsibilities -- expanded. Husbands went to war or went to work in factories in other parts of the country, and the wives had to pick up their husbands' responsibilities. With fewer men in the workforce, women filled more traditionally-male jobs." (http://womenshistory.about.com/od/warwwii/a/overview.htm)
Today though, this scripture is used to make the sisters feel good about not having any "male privileges" because they are responsible for the most important privilege, the preaching work.
In many some lands there is a high femle:male publisher ratio in the congregation, known, informally, as the housewife syndrome. Since most of the preaching is done by sisters during working hours, they are more likely to recruit housewives, which in turn further increase the amount of woman publishers.