you can not use our suggestion for the cr. i recommend to read some articles that compute the compression ratio. so, you can use their values in your comparison and justify your values by depending on their.

JPEG 2000 delivers a typical compression gain in the range of 20%, depending on the image characteristics. Higher-resolution images tend to benefit more, where JPEG-2000's spatial-redundancy prediction can contribute more to the compression process.

Reference

https://en.wikipedia.org/wiki/JPEG_2000

Typically compression ratio for JPEG-LS is around 2:1 for color images. This mode is quite popular in the medical imaging field, and defined as an option in DNG standard. Compression for JPEG-LS is generally much faster than JPEG 2000 and much better than the original lossless JPEG standard.

Reference

https://en.wikipedia.org/wiki/Lossless_JPEG

JPEG2000 is wavelet based hence will provide greater compression (can be lossy or lossless) while LS is(approx) lossless (was used in satellite imagery - I read somewhere ) .

JPEG2000 is used in MPEG for video compression while LS is for stills .

PS- Lossless provides lesser as against lossy . It is also about details for reconstruction that needs to be looked into.

Lossless compression ratios for JPEG2000 are competitive with those provided by JPEG-LS. Moreover, the lossless compression ratios for JPEG 2000 are highly scalable. When comparing JPEG 2000 with JPEG-LS and PNG, even though JPEG 2000 does not perform very well, it still holds its own and can efficiently deal with various image types.

This is where lossless compression ratios for JPEG2000 can help reduce image sizes, while concurrently maintaining the quality of images. In fact, using lossless JPEG2000 compression format a 69 MB file can be compressed to about 12 MB.

Even though lossless compression ratios for JPEG2000 are worse than those got using the JPEG-LS format. However, where lossless compression ratios for JPEG2000 are better is when the format is used to compress pictures from digital cameras. Another plus point that works in the favor of JPEG2000 compression format is that it is widely supported, compatible with various software and is also scalable. In fact with lossless compression ratios for JPEG2000 set at an extreme 1:20 ratio JPEG2000 still performs better than JPEG.