Sometimes it's useful to know which years have been indexed and which have not.

Nuestra Señora de Belén, Mineral de los Asientos de Ibarra, Aguascalientes
As of 18 Jun 2011
Bautismos
No indexes before 1766
Asientos 1766-1769 Mexico-EASy 1410924 batch # C64621-3, 889 results
Asientos 1775-1791 Mexico-EASy 1156077 batch # C03128-8, 5703 results (españoles volume 4?)
Asientos 1810-1821 Mexico-EASy 1156078 batch # C03861-5, 3383 results (vols 15-16)
Asientos 1821-1832, 1835-1838 Mexico-EASy 1410792 batch # C02537-7, 8734 results (prob vols 17, 18, 20)
Asientos 1818-1829 Mexico-EASy 1156079 batch # I04566-2, 2761 results ()
Asientos 1839-1844 Mexico-EASy 1156080 batch # C03861-6, 4548 results (vols 21-22)
Asientos 1844-1855 Mexico-EASy 1156081 batch # C03861-7, 6455 results (vols 23-25)
Asientos 1855-1856 Mexico-EASy 1156082 batch # I06667-9, 747 results ()
Asientos 1856-1858 Mexico-EASy 1156082 batch # I06668-0, 1252 results ()
Asientos 1858-1860 Mexico-EASy 1156082 batch # I06668-1, 1319 results ()
Asientos 1860-1862 Mexico-EASy 1156082 batch # I06668-2, 1234 results ()
Asientos 1862-1865 Mexico-EASy 1156082 batch # I06668-3, 1217 results (vol 28)
Asientos 1865-1871 Mexico-EASy 1156083 batch # C03861-8, 3859 results (vols 29-30)
Asientos 1871-1878 Mexico-EASy 1156084 batch # C02624-9, 4068 results (vols 31-32)
Asientos 1878-1885 Mexico-EASy 1156085 batch # C03861-9, 4336 results (vols 33, 34A, 34B)
No indexes for Asientos Baptisms found after 1885

Matrimonios
Asientos 1706-1729 Mexico-EASy 1410794 batch # M64621-8, 3297 results ()
Asientos 1729-1730 Mexico-EASy 1156091 batch # M01986-8, 154 results ()
Asientos 1744-1755 Mexico-EASy 1710794 batch # M64621-8, 3297 results ()
... (this is the same batch which includes 1706-1729)
No indexes from 1756-1791
Asientos 1792-1829 Mexico-EASy 1156092 batch # M64620-7, 6400 results ()
Asientos 1829-1857 Mexico-EASy 1156093 batch # M64620-8, 7937 results ()
Asientos 1857-1861, 1875-1893 Mexico-EASy 1156094 batch # M64620-9, 4695 results () plus 4 in 1870-1871
None after 1893