Rate per 100,000 (1000 = 1%). Δ is one week.
Data from mass.gov: 2010-08-12, 2010-08-05, 2010-07-29, 2010-07-22, 2010-07-15, 2010-07-08, 2010-07-01, 2010-06-24, 2010-06-17, 2010-06-10, 2010-06-03, 2010-05-27, 2010-05-20, 2010-05-13, 2010-05-06, 2010-04-29, 2010-04-22, 2010-04-15 as of 10 am. Exact number not reported for municipalities with 1–5 cases. Negative numbers can occur if cases have been reassigned to another town in a subsequent week.