Reading is basically about decoding the message. Merely skimming through can give you the information but not the deeper knowledge that a text contains. Therefore, you need to first of all accept the fact that reading is a much more serious exercise than most people would like to concede.
Secondly, reading for deeper meaning and retention and quantitative assessment of how many pages you read don't go hand in hand. Reading is qualitative. You may read less and yet develop a profound understanding. Therefore, you should focus on reading smaller quantities and spend more time with a given text for reading and re-readings.
Thirdly, ideas are correlated across a text. Good writers develop paragraphs which are in continuation of one another. So if you don't take into consideration how these paragraphs are developed and ideas are inter-related across the text, you will miss the core message of the text.
All said and done, in this fast-paced world, you need to spend more time with a given text and reflect over the different ideas expressed and see if there are deeper nuances somewhere, without worrying about how many pages you read in a day.
Reading is supposed to be slow process. Reading for pleasure and information has diluted the profundity that reading once epitomized.