The ideal speed is that of thought. That is, words should be converted into thought instantaneously. The advantages of rapid reading are various: it allows us to get a general view over a topic in very little time, or find a certain piece of information quickly and efficiently. However, it is not always convenient and correct to read so quickly. For instance, a beautiful text, or a book that is very intricate and profound, needs calm, concentrated reading, at low speed. Therefore, a good reader is never monotonous, as he always knows how to adapt the reading speed to the type of text and the aims he has got in regard to it.
The average reader reads at around 50% of his possibilities. If you take a book right now and start reading, you will probably read at a speed of 240-250 words per minute, but with a little training and following the guidelines in this article, in less than two weeks you will be able to read 100 words more per minute, to reach a level of about 350-360 words. If you continue to practice, you will finally manage to read close to 500 words per minute, with the same level of comprehension you have now.