TAIPEI (Taiwan News) — The economy heated up in September following four months of stable growth, the National Development Council said Tuesday.

Under the council’s color-light system, the overall indicator flashed yellow-red in September for the first time since April, per CNA. During the previous four months, the light was green, indicating stable growth.

The total score rose four points to 35 from August to September. Manufacturing sales showed a red light, the top tier in the ranking of indicators, while share prices posted a yellow-red light.

Wholesale, retail, and food and beverage improved to yellow-red, while six other elements did not change, according to the NDC.

While the domestic economy remains stable, officials said it is still necessary to closely monitor developments in the near future.

According to Taiwan’s system of economic indicators, blue stands for contraction, yellow-blue represents sluggishness, green indicates stable growth, yellow-red signals a warming economy, and red means the economy is booming or overheating.