Rabbi Yakov Horowitz writes:
…Viewed from a historical perspective, the ‘drop-out’ rate from Orthodox Jewry in the past fifty years is far lower than it was during the tumultuous hundred years that preceded the generation of our parents – from 1850 to 1950. I would estimate that during the past few decades, about five to fifteen percent of children from observant homes left Yiddishkeit – which is far more than we would like to admit or believe. But bear in mind that the ‘drop-out’ rate was much, much higher in the Lower East Side at the turn of the century, in Yerushalayim in the Thirties and Forties, and in many Chassidish, Litvish, and Ashkenasic communities in pre-war Europe during the height of the haskalah…
Rabbi Horowitz goes on to list a number of commonsense solutions to this problem, most of them ignored by a haredi leadership more interested in ignoring internal problems and blaming the Other. (As I write this, Agudath Israel's anti-blogger session is in full steam.)
But I think there is one important point about the dropout rate not mentioned. – it appears to be rapidly increasing. Why? More on this later.