Ratings for this week’s episodes of Merlin, NBC’s prime-time retelling of the King Arthur legend, fell even further from last week’s lackluster American debut.

The ratings for the show’s first two episodes, which aired a week ago Sunday, averaged 5.35 million viewers, with a 1.35/4.5 rating share in the coveted 18-49 demo (meaning 4.5% of that demographic’s members were watching TV at that time, and 1.35% of them were watching Merlin).

Two more episodes aired this week, and preliminary data suggest that only about 4.27 million viewers watched them, with a 1.0/3 share in the 18-49 demo (though these numbers, based on same-night viewership, will almost certainly be adjusted somewhat upward as viewers who recorded the show watch it later).

These are ordinarily terrible numbers for a broadcast network show, but not only is overall viewership always down in the summer, the broadcast networks have been seeing an overall decline for years, and the decline seems to be particularly steep this summer.

As it did last week, Merlin came in second place in its time-slot, tying with an episode of Extreme Makeover: Home Edition in the first hour, and an episode of Cold Case in the second.

That said, both those shows, and the shows that came in first in the time-slot, The Simpsons, King of the Hill, Family Guy, and American Dad, were reruns.

If there’s a bright spot for Merlin, it’s that the rest of the NBC’s weekly schedule is faring even worse. Last week’s episode of Merlin actually ended up being among the network’s highest rating shows for the week.

Merlin, NBC’s heavily-promoted effort to bring high fantasy to American prime-time, seemed to draw lack-luster ratings in last night’s two-hour premiere.

In the Nielsen overnight ratings, an imprecise number that is often adjusted significantly before “final” ratings are issued, the show drew 5.9 million viewers (a 1.5 share in the coveted 18-49 demo) in the first hour and 4.9 million viewers (a 1.3 18-49 share) in the second hour.

Of the five broadcast networks, the show came in second at both 8 PM (losing to a rerun of the The Simpsons), and 9 PM (losing to a rerun of Family Guy, which drew almost twice as many viewers).

Merlin’s relative failure with viewers may be particularly bad for the show’s prospects as all of its competition in both time-slots (except for a TV movie on the CW) was reruns.

NBC’s previous attempt at prime-time fantasy, Kings, which premiered in March on the same night, was considered an outright bomb, although it drew slightly more viewers than Merlin. Overall viewership is generally down in the summer months, and the network may take that into consideration when deciding Merlin’s fate.

Nielsen’s overnight ratings are more imprecise than “final” ratings issued later in the week. In addition to “live broadcast viewers” — those viewers who watch the program during the live broadcast — they include only partial DVR viewership. 24.4% of all U.S. households now include a DVR.