The ornamental design for the electric meter, as shown and described.
FIG. 1 is a perspective view of the electric meter showing the new design;
FIG. 2 is a front view of the new design;
FIG. 3 is a rear view of the new design;
FIG. 4 is a left view of the new design;
FIG. 5 is a right view of the new design;
FIG. 6 is a top view of the new design; and
FIG. 7 is a bottom view of the new design; and,
FIG. 8 is a perspective view showing a status of the new design in use.
The broken line showing of structural features is included for the purpose of illustrating non-claimed subject matter and forms no part of the claimed design.