Just as a note.
In general we don't count infantry regiments (or armor regiments) when we sum of the strengths of various militaries. The exact number of conventional regiments have never been (nor will be) nailed down.
Sad ya'll don't note that, there are plenty of heavy tanks with more firepower than most mechs, and a heavy tank regiment would pretty much always maul light mech battalion.... BV wise. Many 3025 level heavy tanks (60-75 tons) are around 1000 BV... right up there with medium mechs.
There are a couple instances of these numbers being published which are, IMO, invaluable:
20 Year Update FRR: 15 Mech, 32 Tank, 97 Infantry (over half mechanized), and 62 militia regiments
Original Marik Book: 60 Mech Regiments, 700 non-mech regiments (about 400 infantry, 80 armor, and 100-150 special battalions)
Tikonov Free Republic: 3 mech regiments, 18 Armor Regiments, ~36 Infantry Regiments
SLDF book with all the divisions (2254 Mech Regiments (8% LAM), 2317 Conventional Regiments (24% artillery), 1673 Aerospace Wings (32% Transport, 32% Conventional), 2665 Infantry Regiments (13% Engineer)