How to tell how much sugar is in these wines?

[Kcwhippet]

As Ik says, there is no real correlation between the percentage of alcohol in a wine and any residual sugar. The alcohol depends on the brix the grapes were harvested at and the amount of sugar the winemaker chooses to have present after fermentation. Of course, that doesn't consider that some winemakers choose to add some sweetener after fermentation and before bottling to bring the sugar up to a level that they feel is necessary to sell their product to a particular segment of the market. Many novice/uninformed/uneducated people don't like a completely dry wine preferring some sweetness or perception of sweetness. The winemakers who are trying to sell to that group tend to sell wines with some residual sugar or added sweeteners.