That is not too far off the average of about 550,000 airline miles redeemed per year. I haven't changed my pattern, try to use them as fast as I can (but still seem to have around 500,000 doing nothing):
449,000 AC in 2001
100,000 Hilton in 2001
590,000 AC in 2000
357,000 AC in 1999
730,000 AC in 1998