上升：Increase ,rise ,grow ,go up, climb, jump, soar, surge
下降: decrease, decline, fall, go down, drop, plunge, plummet
波动：fluctuate， vibrate， vary
持平：remain，stay， keep stable， unchanged at
变化幅度小：gradually moderately， modestly，slightly
句式一：描述对象+ 趋势动词（+副词）+ 数据+ 时间区间
The proportion of population aged 65 and over in Japan(描述对象) decreased(趋势动词) from 5% in 1940 to 3% in 1960（数据+时间）.
句式二：There be + 趋势名词 + In + 描述对象 + 时间与数据
There was(There be ) a downward trend （趋势名词）in （IN）the proportion of population aged 65 and over in Japan(描述对象) from 5% in 1940 to 3% in 1960(数据+时间）.
句式三：描述对象+ witness/ experience/ see + 趋势名词 + 数据与时间
The proportion of population aged 65 and over in Japan(描述对象) witnessed a downward trend(趋势名词) from 5% in 1940 to 3% in 1960（时间与数据）.
Be expected / predicted/ estimated to
The proportion of elderly people in Japan is expected to soar from the year 2030.
The three pie chart compare the popularity of five kinds of books according to the sales of bookseller during the period from 1972 and 2012.
Between and- from to/ during the period
Show- describe/ illustrate/reveal/give information about
It’s noticeable that fictions witnessed a gradual rise during the whole period. In 1972, the percentage of adult fiction and childern’s fiction equaled, which was 20%. And then the proportion of adult fiction soared to 45% in the following 40 years, whereas the figure of children’s fiction experienced a steady growth and arrived at 25% in the year 2012.
In contrast, sales of biography and other books showed a decreasing trend, despite that biography was less popular than other books in there three separate years, and the gaps were 5%, 5% and 4% respectively. As for travel books, they gained the least popularity of 15% in 1972, and rose slightly by the year 1992, yet the figure dropped in the rest years and reached 10% in 2012.
Overall, the popularity of fictions increased considerably during the whole period while the popularity of other categories of books saw a marked decrease.