【答案解析】From the given graph. we Call see two peaks of over 30% birth rate. One is around 1950, just after liberation. That's because the long-lasting War ended and the society Was comparatively stable and there was economic increase which raised the living standard of the people. The other is around 1963. that's because after the low birth rate brought by the natural disasters from 1958 to 1961, the birth rate jumped probably to the same level of the first peak. After the two peaks, the general trend of the birth rate is on the decrease. Firstly, that's because of the family planning program advocated by the government; Secondly, the people have gradually realized the importance and the benefits of the program and consciously carried out the policy. The graph displays a vivid historical changes of the birth rate in our country.