Comprehensive forecasts are still not possible.
http://www.spacedaily.com/reports/Can_We_Predict_When_An_Asteroid_Will_Impact_Earth_999.html
NASA claims a cumulative probability of collision over the next 100 years at 0.022% and doesn’t publish any probabilities prior to 2020.
http://neo.jpl.nasa.gov/risk/2012da14.html
Analysis based on 93 observations spanning 10.166 days
(2012-Feb-23.03431 to 2012-Mar-04.200111)
It is almost certain that previous observations will be found by searching older records. Barring that, more observations will be made in the future. With more observations, especially over a longer baseline, the uncertainty in the orbit will decrease dramatically and the likelihood of a collision in the next century will likely become insignificant.