<prompt> Translate the following text to SwahiliAfter two years of data collection, or a minimum of 20 data points, the control chart should be maintained using only the 20 most recent data points.  <response>: Baada ya miaka miwili ya kukusanya data, au angalau pointi za data 20, chati ya udhibiti inapaswa kudumishwa kwa kutumia tu pointi za data za hivi karibuni. 