How to obtain the h-index or number of publications for a given academic as a function of time? Services like Google Scholar can provide you with the h-index of a given author at present. Is there a way or a service that provides a time series of the h-index (or the number of publications) as a function of time, or even provides a plot of this time series?
Scopus has an author search option. You can then examine a range of graphs that show academic output over time. Many universities have a subscription to Scopus.

As with any citation and  publication based metrics, the values are contingent on the citations and publications included in the underlying database. Scopus is fairly broad, but there is quite a lot of quality control. So the numbers will be quite a bit smaller than for example Google Scholar. Another option might be PublishOrPerish which is a downloadable free program which uses Google Scholar as the underlying data source.

Below I show an example for Albert Bandura (one of the most highly cited psychology researchers) using Scopus. 

Citations per year



Documents by year



h-index by year

I could not see any easy way to just get the h-index by year. However, the h-index tab, does allow you to filter on different years. So you could manually, change the end year and repeatedly obtain the h-index to see how it went up each year.