After a certain medicine is ingested, the number of harmful bacteria remaining in the body declines rapidly. The relationship between the elapsed time \[t\], in minutes, since the medicine is ingested, and the number of harmful bacteria remaining in the body, \[H_{\text{minute}}(t)\], is modeled by the following function: \[H_{\text{minute}}(t)=500{,}000{,}000\cdot (0.2)^{t}\] Complete the following sentence about the rate of change in the number of harmful bacteria remaining in the body in seconds. Round your answer to two decimal places. Every second, the number of harmful bacteria remaining in the body decays by a factor of .