The most updated wait assessment statistics made available shows something that 
line riders are unfortunately well aware of. Service has gotten worse and much so within just the past couple of years. The line which is the only service covering most of the East Bronx and local service on the East Side of Manhattan has been known to carry ridership that rivals lines in the overcrowded metropolises of East Asia. However, by New York standards the has been able to handle those demands like a champ having stood for a long time as one of the most reliable numbered lines. For three straight years between 2004-06 the was rated by noted advocacy group the Straphanger's Campaign as the best line in the subway. However the train in 2015 is riddled with delays and so much so that it now accumulates the most of all subway lines. A third of the time gaps in service end up at least 25% larger than the scheduled gap in service which based on wait assessment performance equals a delay. This number is larger then that of the 
which has been for many years bringing up the rear in service reliability (and has not improved any in it's performance) and is larger to a significant degree then just the year prior on the . In February of 2014 75.3% of trains met wait assessment performance standards and the latest data in June 2015 shows that drop to 66.6%. By comparison the met punctuality standards 67% of the time in June 2015 which was worst of all other lines and the 
which provides a similar service on the West Side of Manhattan is reliable nearly 80% of the time. To make matters worse the had the largest negative deviation from it's expected performance target in 2015 with the MTA expecting the to hold true to form 77% of the time and June's actual performance measuring in at 66.6%. As far as other lines are concerned only the 
saw a negative deviation higher than 5% in June of 2015.
The numbers stated above are gathered by the MTA itself in the case of numbered lines using the ATS train supervision system that allows for countdown clocks at stations. If the numbers seem so bad that they're being made up it's just evidence that they're not. In which case what the hell is going on with the that wasn't say just last year or a few years ago?
http://web.mta.info/persdashboard/performance14.html#
http://web.mta.info/persdashboard/agencies/nyctsubway/cp/392312_chartmth.htm