What percentage of users were using Internet Explorer during the period in which 2.1% were using mobile browsers?
CREATE TABLE "usage_share_data_from_wikimedia_visitor_" (
  "period" text,
  "internet_explorer" text,
  "firefox" text,
  "chrome" text,
  "safari" text,
  "opera" text,
  "other_mozilla" text,
  "mobile" text
);
SELECT "internet_explorer" FROM "usage_share_data_from_wikimedia_visitor_" WHERE "mobile"='2.1%';