Weekly, 1865-
Weekly (except for the first week of Jan., and biweekly in July and Aug.)
Weekly (except for 7 double issues published the 2nd week in Jan., the 1st week in Mar., and from the 1st week in July through the 2nd week in Sept., <Nov. 26, 2012->
34 times a year (4 issues in Mar., Apr., and Oct.; 3 issues in Jan., Feb., July, and Nov.; 2 issues in May, June, Aug., Sept., and Dec.), <July 31/Aug. 7, 2017->