TSI Data
Take look at the TSI reconstruction, keep in mind that yes there is a lot of lead lag in the system like James stated.
NASA - Solar Variability: Striking a Balance with Climate Change
Says the slight increase has increased global temperatures by 25% of what has been measured.
NASA - NASA Study Finds Increasing Solar Trend That Can Change Climate
Reports 0.1% increase over the last 24 years...
All of them play down how much warming the sun is responsible, but if you look back where I calculated the solar influence without feedbacks to the CO2 influence with feedbacks. Yes solar activity did decrease to a relatively low solar minimum, but we are now into the next solar maximum, which if you look at my first link you will see it is shaping up to be warmer on average than the last solar maximum (which set record temperatures).
Neil: water, particularly vapor is an interesting and insanely complex issue. On one hand it forms clouds which cool the surface during the day, but insulate from heat loss at night. Evaporation sets up convection currents which carries heat energy higher up into the atmosphere where it can then radiate it out into space. And it is also a very powerfull green house gas.
Whether we or the sun is the cause for the warming increasing water vapor would still be a feedback, but the feedback is only applied to CO2 for comparison, why is that?