Task: Question Answering
Input (English): Passage: On 19 June 1911 the National Constitutional Assembly proclaimed A Portuguesa as the national anthem, replacing the old anthem Hymno da Carta in use since May 1834, and its status as national symbol was included in the new constitution. A Portuguesa was composed in 1890, with music by Alfredo Keil and lyrics by Henrique Lopes de Mendonça, in response to the 1890 British Ultimatum. Because of its patriotic character, it had been used, with slight modifications, by the rebels of the 1891 uprising in a failed attempt at a coup d'état to establish a republic in Portugal, an event which caused the anthem to be forbidden by the monarchic authorities. 
Question: How many years after A Portuguesa was composed was it proclaimed as the national anthem? 
Answer type: Number 
Output (English): 21.