100 mbps means 100 mega bits per second. That's the official speed plan you are on. But, due to overhead loss such as distance from supplier/ISP, also loss due to equipment used, etc. which means you may lose between 15-25% of purchased speed. LW refers to speed in Bytes per second, not bits per second. Divide the speed by 8 will give you bytes.

Download speeds in LW are dependent on your sources/hosts. You can only download as fast as they will let you. Whilst they may be high speed connections, they may already be sharing their upload capacity with 5, 10 or 50 other people so that speed gets divided. Normally in LW you download from several hosts who give you a portion of their upload bandwidth. Ideally you try to download from as many sources/hosts as possible.

To find out what your upload & download speeds are, do a speed test -> Choose nearest location for a speed test & only have your browser open: Speed Test Internet Speed Test DSL Speed Test Broadband Speed Test Bandwidth Speed Test
But note, many of those speed tests specify speeds in bits per second (bps) & not B/S, so divide the result by 8 to show what capacity speed you have in bytes per second.
eg: 100 mbps - 20% overhead = 80 mbps. _____ 80 mbps divided by 8 = 10 MB/s