This site allows you to find the frequency of nearly 150 different grammatical features (pronouns, tense, clauses, etc) in 20 different registers of Modern Spanish (e.g. conversation, fiction, newspapers, academic). It also lets you see examples of each of these constructions in context, from a 20 million word corpus of Spanish, taken from the 100 million word Corpus del Espaņol.
You can perform two types of searches:
1) Find the frequency of a given feature in all 20 registers. Do this by using the form to the left above.
2) Find which features are more common in one register than in another register (e.g. conversation vs newspapers). Do this by using the form to the right above.
In both cases, you can click on any of the entries in the results set to see "Keyword in Context" examples from the corpus itself.