The parliament in the U.K. passes something on the order of 30 to 40 statutes in a two year session. In the 1970s, it was closer to ca. 80 per two year session.
About three-quarters of those bills are "government bills" sponsored by the Prime Minister and his or her cabinet. Only about a quarter of the bills that pass are sponsored by individual legislators as opposed to as part of a cabinet program of legislation. Only about one in 100 individual legislators gets legislation passed in a given session.
Keep in mind that the parliament in the U.K. is serving, for England at least, as not only the equivalent of Congress in the U.S., but also as the equivalent of a state legislature, and is also serving some of the roles served by local governments in the U.S. because local governments in the U.K. have far less autonomy than in the U.S.
Yet, Congress passes 300 to 600 or so bills per two year session, and a typical state legislature passes hundreds of bills per year, and local governments that have autonomy lacking in the U.K. also pass a significant amount of legislation. Taking the 114th Session of Congress as an example, many of those bills are trivialities, but far more than 30-40 of them involve matters of substance. Fore example, by my count, there were 100 bills passed in the 114th Session that were more than extensions of existing programs, symbolic and naming legislation, directions regarding how administration discretion should be authorized, or appropriations, and were instead substantive legislation.
Apparently there are alternatives to parliamentary legislation in the U.K. such as "statutory instruments or Orders in Council" and government agencies simply have more authority than in the U.S., but it isn't as if the United States does not empower its agencies to pass regulations and its heads of government to pass executive orders.