Query cache

I would like to get some opinions about our query cache. Bellow is our query cache stats:
"query_cache": {
"memory_size_in_bytes": 29537552,
"total_count": 144333168499,
"hit_count": 11702200196,
"miss_count": 132630968303,
"cache_size": 2557,
"cache_count": 1313500,
"evictions": 1310943

\what do you think by looking at the numbers? My first reaction was cache size was too small. I have the following in elasticsearch.yml:
indicies.queries.cache.size: 20%

Heapsize 8 GB, total physical memory on the box is 16 GB.