Task: Question Understanding
Input (English): Passage: On 14 August the British entered the city. They had obtained possession of the most important harbour in the Spanish West Indies along with military equipment, 1,828,116 Spanish pesos and merchandise valued around 1,000,000 Spanish pesos. Furthermore, they had seized 20% of the ships of the line of the Spanish Navy, namely Aquilón , Conquistador , Reina , San Antonio , Tigre , San Jenaro , África , América , Infante  and Soberano , together with 3 frigates, 9 smaller vessels including the Marte  commanded by Domingo de Bonechea and some armed vessels belonging to trading companies . Furthermore, two new almost-completed ships of the line were seized in the dockyards - San Carlos  and Santiago .
Question: How many ships in percent did the British not seize?
Output (English): number