Answer:
This depends on many factors - the rating of the solar panel (some produce more than others), the location (some places receive more solar hours than others), the direction of the solar panel (in the Northern Hemisphere, South-facing tilted basically at the same degree as the latitude is optimum), etc.
So, there's no quick, easy answer to this question.
However, to give you a general answer - the typical solar panel installed on homes and businesses is rated at about 200 Watts. A typical panel installed at optimum direction and angle in LA will produce about 290 kWh/year. The same panel at optimum direction and angle in NYC will produce about 240 kWh/year.
To do your own calculations, check out the NREL PVWatts Solar calculator listed in the links below.