Synonyms for Accumulated (same or very similar meaning)
WordNet sense 1 (periodically accumulated over time):
accruedWordNet sense 2 (made greater in size or amount or degree):
increasedWordNet sense 3 (brought together into a group or crowd):
collected, congregate, amassed, assembled, massed, congregateWordNet sense 4 (gathered together or made less diffuse):
concentratedFrom the ODE community, based on WordNetadd/edit