Alberts et al, Molecular Biology of the Cell, say that eukaryotic ribosomes add about 2 amino acids per second, and bacterial about 20 per second (5th edition, p 275). These should be taken only as ballpark estimates: the rate certainly will vary from species to species, from cell to cell, from protein to protein. Some cells (reticulocytes, for instance) are professional protein synthesizers. Others, for instance bacterial endospores, do almost no protein synthesis at all.
These authors estimate the translation rate in mouse embryonic stem cells at around 5.5 amino acids/second. There is a lot of variation from gene to gene, even within this one cell type. They even see systematic variation depending on where you are in the gene.