There was a gradual decline in 2003.

2003年，出现了逐渐下降的情况。

There was a gradual decline in 2008.

2008年，出现了逐渐下降的情况。

There continues to be a gradual decline through the 50's.

从40岁到50岁，这些能力会继续逐渐下降。

Around 1900 BC, signs of a gradual decline begin to emerge.

大约在公元前1900年左右，开始出现衰落的迹象。

There has been a gradual decline in the population of the town.

该镇的人口一直在逐渐减少中。