Different hit counts for same qyery string with same index files

[nirma prasad]

Hi All,

I am using Lucene for indexing and searching.
I am getting different hit counts for same query string.
For example first time it gives 10 hits then second time it gives 20 hits
with same index files.
If any one has any idea then please let me know.
I am adding the code:

     IndexSearcher is = new IndexSearcher(IndexFolder);
     Analyzer analyzer = new StandardAnalyzer();
     Query query = QueryParser.parse(queryString , "text", analyzer);
     Hits hits = is.search(query);

Thanks in advance
Nirma