Tramp rates fluctuate with market conditions of supply and demand. In a boom period, the tramp rates rise; in a period of recession, they decline.

不定期船费率随航运市场的供求关系而波动。在市场繁荣时期，不定期船费率上升，在市场萧条时期，费率下降。

Usually I look for a change from the beginning to the end of the period. However, there is no overall trend because the figures fluctuate.

观察整个时期的变化，发现各国犯罪数据波动较大，没有明显主要趋势。

Since 1990s the Chinese real estate market has been in a period of upright development, which may fluctuate for a while but steadily accelerate its speed.

自上世纪九十年代以来，我国房地产市场始终出于上行状态，期间或有起伏，但房价始终昂首向上，且有加速之势。